https://aowis.org/api.php?action=feedcontributions&feedformat=atom&user=Samuel 2026-09-06T12:50:31Z User contributions MediaWiki 1.46.0 https://aowis.org/index.php?title=Main_Page&diff=701 2026-09-05T14:57:58Z

<p>Samuel: </p> <hr /> <div>{{MainPageBanner}}<br /> <br /> {{Header box<br /> | title = Motivation<br /> | color = teal<br /> | body = <br /> <br /> [[File:Countryside.jpg|class=fullwidth|center]]<br /> <br /> In less developed regions, such as rural areas and small towns in Africa, water distribution remains a significant challenge. While NGOs have been successfully supporting communities for decades by drilling wells, installing pumps, and sometimes building water towers, distributing water across a network on the surface is often difficult.<br /> <br /> Local initiatives that take on these projects frequently encounter a situation where operating the system manually becomes unsustainable, requiring constant attention. Qualified personnel are scarce, and suitable technology to support automated or semi-automated operation is either unavailable under local constraints or too expensive.<br /> <br /> This is where AOWIS aims to contribute: by providing an open standard for designing, deploying, and managing water and agricultural infrastructure in such environments. AOWIS supports both the planning phase—helping initiatives evaluate and design systems based on regional conditions such as topography—and the operational phase, including system monitoring, control, and maintenance.<br /> <br /> In addition, AOWIS aims to support the training of local technicians and to collaborate closely with experienced NGOs and local initiatives that already operate and maintain such systems, in order to improve sustainability and reduce operational burden.<br /> }}<br /> <br /> {{Header box<br /> | title = Why an Open Standard is Needed<br /> | color = turquoise<br /> | body = <br /> <br /> [[File:Cooperation.jpg|400px|frameless|right]]<br /> <br /> In environments where infrastructure is built over decades by many different actors using solutions from different vendors and manufacturers, systems become fragmented, forcing operators to manage multiple incompatible tools and workflows while making daily operation, maintenance, expansion, and staff training increasingly complex and costly.<br /> <br /> This fragmentation often results in vendor lock-in, where systems depend on specific tools, expertise, or suppliers that may not remain available over the full lifecycle of the infrastructure.<br /> <br /> An open standard provides a shared technical foundation that enables interoperability and ensures systems can be maintained and extended independently of any single product or provider.<br /> <br /> AOWIS defines such a foundation for water and agricultural infrastructure under real-world operational constraints.<br /> }}<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> {{Header box<br /> | title = Operation Conditions of AOWIS<br /> | color = lightblue<br /> | body =<br /> [[File:Village.jpg|250px|frameless|right]]<br /> <br /> AOWIS is designed to operate under the real-world conditions faced by local initiatives. These include, among others:<br /> <br /> * unreliable power supply<br /> * intermittent connectivity<br /> * diverse or aging equipment<br /> * limited availability of trained personnel<br /> * the need for safety and autonomous operation<br /> <br /> AOWIS enables systems that continue to function safely and reliably, even under degraded or adverse conditions.<br /> }}<br /> <br /> {{Header box<br /> | title = Facing the Challenges<br /> | color = lightblue<br /> | body = <br /> AOWIS addresses these operational challenges through the following principles:<br /> <br /> * human-in-the-loop control<br /> * offline-first operation<br /> * safe fallback behavior<br /> * modular and extensible logic<br /> * shared infrastructure models<br /> * training programs for local operators<br /> * transparent governance<br /> <br /> The goal is to make essential systems '''robust, maintainable, and locally operable'''.<br /> }}<br /> &lt;/div&gt;<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> <br /> {{Header box<br /> | title = Start Here<br /> | color = yellow<br /> | body =<br /> If you are new to AOWIS, begin with:<br /> <br /> * [[Concepts:Design_Philosophy|Design Philosophy]] <br /> * [[Standard:Definitions|Definitions]] <br /> * [[Standard:Normative_Requirements|Normative Requirements]] <br /> * [[Modules:Module_Template|Module Template]] <br /> * [[AOWIS:Contributor_Guide_External|Contributor Guide - External]]<br /> * [[AOWIS:Contributor_Guide_Internal|Contributor Guide - Internal]]<br /> * [[AOWIS:Writing_Style_Guide|Writing Style Guide]]<br /> * [[AOWIS:AI_Usage_Guide|AI Usage Guide]]<br /> * [[AOWIS:Research_Form_Guide|Research Form Guide]]<br /> * [[AOWIS:Naming_Convention_Specification|Naming Convention Specification]]<br /> * [[AOWIS:Change_Log__Versioning|Change Log &amp; Versioning]]<br /> * [[AOWIS:Wiki|This Wiki]]<br /> <br /> These pages explain how to read, use, and contribute to the standard.<br /> }}<br /> <br /> {{Header box<br /> | title = List of Requirement Pages<br /> | color = brown<br /> | body = <br /> This index lists AOWIS pages that define normative requirements (MUST/SHOULD/MAY statements) and conformance rules.<br /> <br /> '''Dev Rules''' — specs for writing and maintaining AOWIS<br /> <br /> * '''REQ-AI:''' [[AOWIS:AI_Usage_Guide|AI Usage Guide]]<br /> <br /> '''Technical Standard''' — system behavior and data models<br /> <br /> * '''REQ-MEAS, REQ-MEAS-UI:''' [[Measurement:Units|Unit System Requirements]]<br /> * '''REQ-MEAS-UNI:''' [[Measurement:Unit_Identifiers|Unit Identifiers]]<br /> }}<br /> <br /> &lt;/div&gt;<br /> <br /> {{Header box<br /> | title = AOWIS Documentation Structure<br /> | color = purple<br /> | body = <br /> AOWIS documentation is organized into dedicated namespaces with clearly separated purposes.<br /> <br /> The [[Standard:Main_Page|Standard]] namespace contains the normative requirements that define AOWIS compliance. The other namespaces provide the motivation, concepts, engineering knowledge, architectures, operational models, implementation guidance, reference designs, training material, and supporting information needed to understand, implement, and operate AOWIS systems.<br /> <br /> * [[Motivation:Main_Page|Motivation]] – Causal justification of design requirements based on real-world failures, constraints, and operational realities.<br /> * [[Standard:Main_Page|Standard]] – The normative core of AOWIS. Defines requirements and definitions specifying what AOWIS-compliant systems MUST, SHOULD, or MAY do.<br /> * [[Concepts:Main_Page|Concepts]] – Core ideas, philosophy, rationale, and contextual understanding that explain AOWIS without prescribing a specific implementation.<br /> * [[Architecture:Main_Page|Architecture]] – High-level system structure, including controllers, layers, communication, data flows, and their interactions.<br /> * [[Infrastructure:Main_Page|Infrastructure]] – Physical technologies, systems, and components used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints.<br /> * [[Measurement:Main_Page|Measurement]] – Definition and handling of sensor data, manual measurements, calibration, uncertainty, and derived physical values.<br /> * [[Data:Main_Page|Data]] – Data models, schemas, logging structures, synchronization formats, and data lifecycle rules.<br /> * [[Operations:Main_Page|Operations]] – Runtime behavior, control logic, state transitions, fallback behavior, and decision-making during system operation.<br /> * [[Modules:Main_Page|Modules]] – Reusable functional extensions that provide domain-specific capabilities within AOWIS.<br /> * [[Reference:Main_Page|Reference]] – Non-normative concrete implementations, engineering blueprints, example deployments, and validated design patterns showing specific ways AOWIS systems may be built.<br /> * [[Databases:Main_Page|Databases]] – Federated knowledge bases and structured supporting information used by AOWIS implementations.<br /> * [[Governance:Main_Page|Governance]] – Certification, compliance, auditing, trust, licensing, versioning, and organizational governance.<br /> * [[Training:Main_Page|Training]] – Operator education, technical training, field guidance, documentation literacy, and capacity building.<br /> * [[External:Main_Page|External]] – External projects, standards, technologies, and systems that relate to or influence AOWIS.<br /> <br /> For a full overview, see the [[AOWIS:Table_of_Contents|Table of Contents]].<br /> }}<br /> <br /> {{Header box<br /> | title = Roadmap<br /> | color = grey<br /> | body =<br /> [[File:Boring.jpg|250px|frameless|right]]<br /> <br /> == Roadmap ==<br /> <br /> AOWIS has progressed beyond its initial conceptual phase. A substantial software foundation for modelling, simulating, visualizing, and eventually operating water infrastructure is under active development.<br /> <br /> The long-term objective is a complete open-source '''SCADA, infrastructure modelling, simulation, and operational management platform''' for water and agricultural infrastructure. Planning, simulation, live monitoring, control, maintenance, and historical data should ultimately operate on the same shared infrastructure model.<br /> <br /> EPANET currently provides the primary hydraulic and water-quality simulation engine, but AOWIS is not designed as an EPANET frontend. EPANET is one solver integrated into a broader, solver-independent AOWIS architecture.<br /> <br /> === Current Software State ===<br /> <br /> The current AOWIS software stack already includes several major components:<br /> <br /> ; '''Shared infrastructure model'''<br /> : The AOWIS server model provides a common representation of water infrastructure independently of a particular simulator, user interface, or field controller. Pumps, pipes, junctions, reservoirs, tanks, valves, controls, measurements, and related infrastructure can therefore be represented consistently throughout the system.<br /> <br /> ; '''Hydraulic and water-quality simulation'''<br /> : A dedicated EPANET integration layer translates between the AOWIS model and EPANET and executes hydraulic and water-quality simulations. The integration supports network import and export, hydraulic behaviour, controls and rules, pumps and valves, water-quality analysis, diagnostics, simulation reports, and other EPANET functionality.<br /> :<br /> : Integration of '''EPANET-MSX''' is being developed to extend this to advanced multi-species water-quality and chemical reaction modelling.<br /> <br /> ; '''Network editor and monitoring interface'''<br /> : The AOWIS graphical application provides tools for creating, importing, inspecting, simulating, and visualizing water networks. This includes geographic map views, terrain-aware 3D visualization, network monitoring views, simulation configuration, and analysis of simulation results.<br /> <br /> ; '''Geographic and terrain infrastructure'''<br /> : AOWIS includes mapping and terrain services for geographic placement, elevation data, basemaps, terrain visualization, and local caching. This allows hydraulic infrastructure to be evaluated together with the real terrain on which it is or may be constructed.<br /> <br /> ; '''Local and standalone operation'''<br /> : AOWIS is being designed so that deployments do not depend on continuous Internet or cloud connectivity. Server, map, simulation, and user-interface components can be combined for local deployments, supporting the offline-first requirements of the project.<br /> <br /> The software remains under active development and should not yet be considered a complete production SCADA system.<br /> <br /> === Towards a Full SCADA System ===<br /> <br /> The next major development stage is to connect the existing infrastructure model and simulation environment to '''real infrastructure in continuous operation'''.<br /> <br /> The same network that is used for planning and hydraulic simulation should eventually represent the live system:<br /> <br /> * sensor measurements update the state of modelled infrastructure<br /> * pumps, valves, tanks, reservoirs, wells, treatment systems, and electrical systems can be monitored in real time<br /> * historical measurements and operational events are recorded<br /> * operators can inspect current and historical system behaviour<br /> * alarms and abnormal conditions are detected and presented clearly<br /> * hydraulic and water-quality models can be compared with observed conditions<br /> * authorized control commands can be issued to field equipment<br /> * automation can operate within explicitly defined safety limits<br /> * local systems continue operating safely when communication with higher-level systems is unavailable<br /> <br /> === Telemetry and Field Communication ===<br /> <br /> Initial AOWIS deployments are intended to use technologies such as:<br /> <br /> * [[Architecture:Protocols:LoRa/LoRaWAN]] for low-bandwidth long-range field communication<br /> * [[Architecture:Protocols:MQTT]] for telemetry and message transport<br /> <br /> The architecture should remain open to additional field and industrial protocols as required.<br /> <br /> Future work includes:<br /> <br /> * standardized representation of sensors, actuators, controllers, and communication endpoints<br /> * ingestion of continuous and event-based telemetry<br /> * manual measurements alongside automated measurements<br /> * reliable timestamping and measurement quality information<br /> * buffering during communication outages<br /> * synchronization after connectivity is restored<br /> * device health and communication-state monitoring<br /> <br /> === Monitoring, Alarms, and Historian ===<br /> <br /> AOWIS is intended to develop from its current simulation and visualization capabilities into a complete operational monitoring environment.<br /> <br /> Planned capabilities include:<br /> <br /> * live network status<br /> * time-series storage and visualization<br /> * alarm and event management<br /> * configurable alarm thresholds and priorities<br /> * acknowledgement and audit trails<br /> * equipment status and fault reporting<br /> * operational dashboards<br /> * maintenance information<br /> * comparison of measured and simulated behaviour<br /> * long-term analysis of water demand, pressure, flow, quality, energy use, and equipment performance<br /> <br /> === Control and Automation ===<br /> <br /> AOWIS ultimately aims to support both manual and automatic control of infrastructure.<br /> <br /> This includes:<br /> <br /> * pumps<br /> * valves and actuators<br /> * storage tanks and water towers<br /> * wells and boreholes<br /> * treatment systems<br /> * irrigation systems<br /> * electrical and solar-energy infrastructure<br /> <br /> Automation must follow the core AOWIS principles of '''human-in-the-loop control, safe fallback behaviour, local autonomy, and operation under degraded conditions'''.<br /> <br /> Safety-critical protection should not depend solely on central software or network connectivity. Where appropriate, fundamental protections should remain implemented locally using simple and independently functioning electrical, mechanical, or controller-based systems.<br /> <br /> === Model-Assisted Operation ===<br /> <br /> A major objective is to combine traditional SCADA functionality with the hydraulic and infrastructure model already present in AOWIS.<br /> <br /> The live system may eventually use simulation and modelling to support:<br /> <br /> * expected-versus-measured pressure and flow comparison<br /> * leak and abnormal-consumption detection<br /> * detection of sensor or equipment faults<br /> * estimation of conditions at locations without sensors<br /> * tank and reservoir management<br /> * pump scheduling<br /> * energy optimization<br /> * water-quality tracking<br /> * evaluation of proposed operator actions before execution<br /> * demand forecasting<br /> * planning of network expansion and infrastructure changes<br /> <br /> This creates a path from a conventional SCADA display toward a continuously updated operational model of the physical water system.<br /> <br /> === Solver-Independent Development ===<br /> <br /> Although EPANET is currently the primary hydraulic solver, hydraulic calculations and solver-specific assumptions should remain isolated from the common AOWIS infrastructure model.<br /> <br /> This allows AOWIS to integrate additional simulators, optimization systems, agricultural models, or specialized engineering tools in the future without requiring the physical infrastructure model to be redesigned around a particular solver.<br /> <br /> === Infrastructure and Water Treatment ===<br /> <br /> Development is also expanding beyond distribution networks themselves.<br /> <br /> AOWIS should be capable of representing and supporting the planning and operation of complete water systems, including:<br /> <br /> * wells and boreholes<br /> * pumping stations<br /> * reservoirs and water towers<br /> * distribution networks<br /> * drinking-water treatment<br /> * desalination<br /> * disinfection<br /> * irrigation<br /> * electrical and solar-energy systems<br /> <br /> See [[Infrastructure:Main_Page|Infrastructure]] for documentation of physical infrastructure technologies and [[Reference:Main_Page|Reference]] for concrete engineering designs and example implementations.<br /> <br /> === Hardware ===<br /> <br /> Hardware development and research will continue alongside the software platform.<br /> <br /> Priorities include:<br /> <br /> * robust water-level, pressure, flow, and water-quality sensing<br /> * monitoring of solar and battery systems<br /> * locally serviceable field controllers<br /> * pump and valve interfaces<br /> * electrical protection<br /> * emergency shutdown systems<br /> * equipment suitable for heat, dust, unreliable power, and difficult logistics<br /> * designs that can be repaired using locally available skills and components where practical<br /> <br /> AOWIS does not require all hardware to be developed specifically for the project. Existing equipment should be integrated wherever it can satisfy the required interfaces, reliability, safety, and maintainability requirements.<br /> <br /> === Long-Term Direction ===<br /> <br /> The intended result is an integrated platform covering the complete lifecycle of water infrastructure:<br /> <br /> '''survey and planning → engineering and simulation → construction → commissioning → monitoring → control → maintenance → analysis → expansion'''<br /> <br /> The same open infrastructure model should connect these stages instead of requiring separate, incompatible systems for engineering, SCADA, maintenance, mapping, and simulation.<br /> <br /> AOWIS aims to make capabilities that are traditionally distributed across expensive and proprietary engineering, GIS, SCADA, telemetry, and asset-management products available through an open and interoperable platform suitable for both small local installations and larger water systems.<br /> }}<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> {{Header box<br /> | title = Governance &amp; Legitimacy<br /> | color = turquoise<br /> | body = <br /> AOWIS includes a transparent governance model to ensure:<br /> <br /> * open participation <br /> * clear certification processes <br /> * stable versioning <br /> * long‑term protection of the standard <br /> <br /> See: [[Governance:Main_Page|Governance]].<br /> }}<br /> <br /> {{Header box<br /> | title = Navigation<br /> | color = grey<br /> | body =<br /> * [[AOWIS:Table_of_Contents|Table of Contents]] <br /> * [[Reference:Glossary|Glossary]] <br /> * [[Reference:FAQ|FAQ]] <br /> * [[Reference:Change_Log|Change Log]] <br /> <br /> * [https://github.com/aowis-org GitHub]<br /> }}<br /> &lt;/div&gt;<br /> <br /> {{Header box<br /> | title = Partners<br /> | color = indigo<br /> | body = <br /> [[File:Afriticgroup.webp|250px|frameless|center|link=https://afriticgroup.com/]]<br /> }}<br /> <br /> ''AOWIS is an open, evolving standard. Contributions are welcome. For contact, please visit us on [https://github.com/aowis-org GitHub]''</div>

Samuel https://aowis.org/index.php?title=Main_Page&diff=700 2026-09-05T14:55:50Z

<p>Samuel: </p> <hr /> <div>{{MainPageBanner}}<br /> <br /> {{Header box<br /> | title = Motivation<br /> | color = teal<br /> | body = <br /> <br /> [[File:Countryside.jpg|class=fullwidth|center]]<br /> <br /> In less developed regions, such as rural areas and small towns in Africa, water distribution remains a significant challenge. While NGOs have been successfully supporting communities for decades by drilling wells, installing pumps, and sometimes building water towers, distributing water across a network on the surface is often difficult.<br /> <br /> Local initiatives that take on these projects frequently encounter a situation where operating the system manually becomes unsustainable, requiring constant attention. Qualified personnel are scarce, and suitable technology to support automated or semi-automated operation is either unavailable under local constraints or too expensive.<br /> <br /> This is where AOWIS aims to contribute: by providing an open standard for designing, deploying, and managing water and agricultural infrastructure in such environments. AOWIS supports both the planning phase—helping initiatives evaluate and design systems based on regional conditions such as topography—and the operational phase, including system monitoring, control, and maintenance.<br /> <br /> In addition, AOWIS aims to support the training of local technicians and to collaborate closely with experienced NGOs and local initiatives that already operate and maintain such systems, in order to improve sustainability and reduce operational burden.<br /> }}<br /> <br /> {{Header box<br /> | title = Why an Open Standard is Needed<br /> | color = turquoise<br /> | body = <br /> <br /> [[File:Cooperation.jpg|400px|frameless|right]]<br /> <br /> In environments where infrastructure is built over decades by many different actors using solutions from different vendors and manufacturers, systems become fragmented, forcing operators to manage multiple incompatible tools and workflows while making daily operation, maintenance, expansion, and staff training increasingly complex and costly.<br /> <br /> This fragmentation often results in vendor lock-in, where systems depend on specific tools, expertise, or suppliers that may not remain available over the full lifecycle of the infrastructure.<br /> <br /> An open standard provides a shared technical foundation that enables interoperability and ensures systems can be maintained and extended independently of any single product or provider.<br /> <br /> AOWIS defines such a foundation for water and agricultural infrastructure under real-world operational constraints.<br /> }}<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> {{Header box<br /> | title = Operation Conditions of AOWIS<br /> | color = lightblue<br /> | body =<br /> [[File:Village.jpg|250px|frameless|right]]<br /> <br /> AOWIS is designed to operate under the real-world conditions faced by local initiatives. These include, among others:<br /> <br /> * unreliable power supply<br /> * intermittent connectivity<br /> * diverse or aging equipment<br /> * limited availability of trained personnel<br /> * the need for safety and autonomous operation<br /> <br /> AOWIS enables systems that continue to function safely and reliably, even under degraded or adverse conditions.<br /> }}<br /> <br /> {{Header box<br /> | title = Facing the Challenges<br /> | color = lightblue<br /> | body = <br /> AOWIS addresses these operational challenges through the following principles:<br /> <br /> * human-in-the-loop control<br /> * offline-first operation<br /> * safe fallback behavior<br /> * modular and extensible logic<br /> * shared infrastructure models<br /> * training programs for local operators<br /> * transparent governance<br /> <br /> The goal is to make essential systems '''robust, maintainable, and locally operable'''.<br /> }}<br /> &lt;/div&gt;<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> <br /> {{Header box<br /> | title = Start Here<br /> | color = yellow<br /> | body =<br /> If you are new to AOWIS, begin with:<br /> <br /> * [[Concepts:Design_Philosophy|Design Philosophy]] <br /> * [[Standard:Definitions|Definitions]] <br /> * [[Standard:Normative_Requirements|Normative Requirements]] <br /> * [[Modules:Module_Template|Module Template]] <br /> * [[AOWIS:Contributor_Guide_External|Contributor Guide - External]]<br /> * [[AOWIS:Contributor_Guide_Internal|Contributor Guide - Internal]]<br /> * [[AOWIS:Writing_Style_Guide|Writing Style Guide]]<br /> * [[AOWIS:AI_Usage_Guide|AI Usage Guide]]<br /> * [[AOWIS:Research_Form_Guide|Research Form Guide]]<br /> * [[AOWIS:Naming_Convention_Specification|Naming Convention Specification]]<br /> * [[AOWIS:Change_Log__Versioning|Change Log &amp; Versioning]]<br /> * [[AOWIS:Wiki|This Wiki]]<br /> <br /> These pages explain how to read, use, and contribute to the standard.<br /> }}<br /> <br /> {{Header box<br /> | title = List of Requirement Pages<br /> | color = brown<br /> | body = <br /> This index lists AOWIS pages that define normative requirements (MUST/SHOULD/MAY statements) and conformance rules.<br /> <br /> '''Dev Rules''' — specs for writing and maintaining AOWIS<br /> <br /> * '''REQ-AI:''' [[AOWIS:AI_Usage_Guide|AI Usage Guide]]<br /> <br /> '''Technical Standard''' — system behavior and data models<br /> <br /> * '''REQ-MEAS, REQ-MEAS-UI:''' [[Measurement:Units|Unit System Requirements]]<br /> * '''REQ-MEAS-UNI:''' [[Measurement:Unit_Identifiers|Unit Identifiers]]<br /> }}<br /> <br /> &lt;/div&gt;<br /> <br /> {{Header box<br /> | title = AOWIS Documentation Structure<br /> | color = purple<br /> | body = <br /> AOWIS documentation is organized into dedicated namespaces with clearly separated purposes.<br /> <br /> The [[Standard:Main_Page|Standard]] namespace contains the normative requirements that define AOWIS compliance. The other namespaces provide the motivation, concepts, engineering knowledge, architectures, operational models, implementation guidance, reference designs, training material, and supporting information needed to understand, implement, and operate AOWIS systems.<br /> <br /> * [[Motivation:Main_Page|Motivation]] – Causal justification of design requirements based on real-world failures, constraints, and operational realities.<br /> * [[Standard:Main_Page|Standard]] – The normative core of AOWIS. Defines requirements and definitions specifying what AOWIS-compliant systems MUST, SHOULD, or MAY do.<br /> * [[Concepts:Main_Page|Concepts]] – Core ideas, philosophy, rationale, and contextual understanding that explain AOWIS without prescribing a specific implementation.<br /> * [[Architecture:Main_Page|Architecture]] – High-level system structure, including controllers, layers, communication, data flows, and their interactions.<br /> * [[Infrastructure:Main_Page|Infrastructure]] – Physical technologies, systems, and components used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints.<br /> * [[Measurement:Main_Page|Measurement]] – Definition and handling of sensor data, manual measurements, calibration, uncertainty, and derived physical values.<br /> * [[Data:Main_Page|Data]] – Data models, schemas, logging structures, synchronization formats, and data lifecycle rules.<br /> * [[Operations:Main_Page|Operations]] – Runtime behavior, control logic, state transitions, fallback behavior, and decision-making during system operation.<br /> * [[Modules:Main_Page|Modules]] – Reusable functional extensions that provide domain-specific capabilities within AOWIS.<br /> * [[Reference:Main_Page|Reference]] – Non-normative concrete implementations, engineering blueprints, example deployments, and validated design patterns showing specific ways AOWIS systems may be built.<br /> * [[Databases:Main_Page|Databases]] – Federated knowledge bases and structured supporting information used by AOWIS implementations.<br /> * [[Governance:Main_Page|Governance]] – Certification, compliance, auditing, trust, licensing, versioning, and organizational governance.<br /> * [[Training:Main_Page|Training]] – Operator education, technical training, field guidance, documentation literacy, and capacity building.<br /> * [[External:Main_Page|External]] – External projects, standards, technologies, and systems that relate to or influence AOWIS.<br /> <br /> For a full overview, see the [[AOWIS:Table_of_Contents|Table of Contents]].<br /> }}<br /> <br /> {{Header box<br /> | title = Roadmap<br /> | color = grey<br /> | body =<br /> [[File:Boring.jpg|250px|frameless|right]]<br /> <br /> == Roadmap ==<br /> <br /> AOWIS has progressed beyond its initial conceptual phase. A substantial software foundation for modelling, simulating, visualizing, and eventually operating water infrastructure is under active development.<br /> <br /> The long-term objective is a complete open-source '''SCADA, infrastructure modelling, simulation, and operational management platform''' for water and agricultural infrastructure. Planning, simulation, live monitoring, control, maintenance, and historical data should ultimately operate on the same shared infrastructure model.<br /> <br /> EPANET currently provides the primary hydraulic and water-quality simulation engine, but AOWIS is not designed as an EPANET frontend. EPANET is one solver integrated into a broader, solver-independent AOWIS architecture.<br /> <br /> === Current Software State ===<br /> <br /> The current AOWIS software stack already includes several major components:<br /> <br /> ; '''Shared infrastructure model'''<br /> : The AOWIS server model provides a common representation of water infrastructure independently of a particular simulator, user interface, or field controller. Pumps, pipes, junctions, reservoirs, tanks, valves, controls, measurements, and related infrastructure can therefore be represented consistently throughout the system.<br /> <br /> ; '''Hydraulic and water-quality simulation'''<br /> : A dedicated EPANET integration layer translates between the AOWIS model and EPANET and executes hydraulic and water-quality simulations. The integration supports network import and export, hydraulic behaviour, controls and rules, pumps and valves, water-quality analysis, diagnostics, simulation reports, and other EPANET functionality.<br /> :<br /> : Integration of '''EPANET-MSX''' is being developed to extend this to advanced multi-species water-quality and chemical reaction modelling.<br /> <br /> ; '''Network editor and monitoring interface'''<br /> : The AOWIS graphical application provides tools for creating, importing, inspecting, simulating, and visualizing water networks. This includes geographic map views, terrain-aware 3D visualization, network monitoring views, simulation configuration, and analysis of simulation results.<br /> <br /> ; '''Geographic and terrain infrastructure'''<br /> : AOWIS includes mapping and terrain services for geographic placement, elevation data, basemaps, terrain visualization, and local caching. This allows hydraulic infrastructure to be evaluated together with the real terrain on which it is or may be constructed.<br /> <br /> ; '''Local and standalone operation'''<br /> : AOWIS is being designed so that deployments do not depend on continuous Internet or cloud connectivity. Server, map, simulation, and user-interface components can be combined for local deployments, supporting the offline-first requirements of the project.<br /> <br /> The software remains under active development and should not yet be considered a complete production SCADA system.<br /> <br /> === Towards a Full SCADA System ===<br /> <br /> The next major development stage is to connect the existing infrastructure model and simulation environment to '''real infrastructure in continuous operation'''.<br /> <br /> The same network that is used for planning and hydraulic simulation should eventually represent the live system:<br /> <br /> * sensor measurements update the state of modelled infrastructure<br /> * pumps, valves, tanks, reservoirs, wells, treatment systems, and electrical systems can be monitored in real time<br /> * historical measurements and operational events are recorded<br /> * operators can inspect current and historical system behaviour<br /> * alarms and abnormal conditions are detected and presented clearly<br /> * hydraulic and water-quality models can be compared with observed conditions<br /> * authorized control commands can be issued to field equipment<br /> * automation can operate within explicitly defined safety limits<br /> * local systems continue operating safely when communication with higher-level systems is unavailable<br /> <br /> === Telemetry and Field Communication ===<br /> <br /> Initial AOWIS deployments are intended to use technologies such as:<br /> <br /> * [[External:LoRaWAN|LoRaWAN]] for low-bandwidth long-range field communication<br /> * [[External:MQTT|MQTT]] for telemetry and message transport<br /> <br /> The architecture should remain open to additional field and industrial protocols as required.<br /> <br /> Future work includes:<br /> <br /> * standardized representation of sensors, actuators, controllers, and communication endpoints<br /> * ingestion of continuous and event-based telemetry<br /> * manual measurements alongside automated measurements<br /> * reliable timestamping and measurement quality information<br /> * buffering during communication outages<br /> * synchronization after connectivity is restored<br /> * device health and communication-state monitoring<br /> <br /> === Monitoring, Alarms, and Historian ===<br /> <br /> AOWIS is intended to develop from its current simulation and visualization capabilities into a complete operational monitoring environment.<br /> <br /> Planned capabilities include:<br /> <br /> * live network status<br /> * time-series storage and visualization<br /> * alarm and event management<br /> * configurable alarm thresholds and priorities<br /> * acknowledgement and audit trails<br /> * equipment status and fault reporting<br /> * operational dashboards<br /> * maintenance information<br /> * comparison of measured and simulated behaviour<br /> * long-term analysis of water demand, pressure, flow, quality, energy use, and equipment performance<br /> <br /> === Control and Automation ===<br /> <br /> AOWIS ultimately aims to support both manual and automatic control of infrastructure.<br /> <br /> This includes:<br /> <br /> * pumps<br /> * valves and actuators<br /> * storage tanks and water towers<br /> * wells and boreholes<br /> * treatment systems<br /> * irrigation systems<br /> * electrical and solar-energy infrastructure<br /> <br /> Automation must follow the core AOWIS principles of '''human-in-the-loop control, safe fallback behaviour, local autonomy, and operation under degraded conditions'''.<br /> <br /> Safety-critical protection should not depend solely on central software or network connectivity. Where appropriate, fundamental protections should remain implemented locally using simple and independently functioning electrical, mechanical, or controller-based systems.<br /> <br /> === Model-Assisted Operation ===<br /> <br /> A major objective is to combine traditional SCADA functionality with the hydraulic and infrastructure model already present in AOWIS.<br /> <br /> The live system may eventually use simulation and modelling to support:<br /> <br /> * expected-versus-measured pressure and flow comparison<br /> * leak and abnormal-consumption detection<br /> * detection of sensor or equipment faults<br /> * estimation of conditions at locations without sensors<br /> * tank and reservoir management<br /> * pump scheduling<br /> * energy optimization<br /> * water-quality tracking<br /> * evaluation of proposed operator actions before execution<br /> * demand forecasting<br /> * planning of network expansion and infrastructure changes<br /> <br /> This creates a path from a conventional SCADA display toward a continuously updated operational model of the physical water system.<br /> <br /> === Solver-Independent Development ===<br /> <br /> Although EPANET is currently the primary hydraulic solver, hydraulic calculations and solver-specific assumptions should remain isolated from the common AOWIS infrastructure model.<br /> <br /> This allows AOWIS to integrate additional simulators, optimization systems, agricultural models, or specialized engineering tools in the future without requiring the physical infrastructure model to be redesigned around a particular solver.<br /> <br /> === Infrastructure and Water Treatment ===<br /> <br /> Development is also expanding beyond distribution networks themselves.<br /> <br /> AOWIS should be capable of representing and supporting the planning and operation of complete water systems, including:<br /> <br /> * wells and boreholes<br /> * pumping stations<br /> * reservoirs and water towers<br /> * distribution networks<br /> * drinking-water treatment<br /> * desalination<br /> * disinfection<br /> * irrigation<br /> * electrical and solar-energy systems<br /> <br /> See [[Infrastructure:Main_Page|Infrastructure]] for documentation of physical infrastructure technologies and [[Reference:Main_Page|Reference]] for concrete engineering designs and example implementations.<br /> <br /> === Hardware ===<br /> <br /> Hardware development and research will continue alongside the software platform.<br /> <br /> Priorities include:<br /> <br /> * robust water-level, pressure, flow, and water-quality sensing<br /> * monitoring of solar and battery systems<br /> * locally serviceable field controllers<br /> * pump and valve interfaces<br /> * electrical protection<br /> * emergency shutdown systems<br /> * equipment suitable for heat, dust, unreliable power, and difficult logistics<br /> * designs that can be repaired using locally available skills and components where practical<br /> <br /> AOWIS does not require all hardware to be developed specifically for the project. Existing equipment should be integrated wherever it can satisfy the required interfaces, reliability, safety, and maintainability requirements.<br /> <br /> === Long-Term Direction ===<br /> <br /> The intended result is an integrated platform covering the complete lifecycle of water infrastructure:<br /> <br /> '''survey and planning → engineering and simulation → construction → commissioning → monitoring → control → maintenance → analysis → expansion'''<br /> <br /> The same open infrastructure model should connect these stages instead of requiring separate, incompatible systems for engineering, SCADA, maintenance, mapping, and simulation.<br /> <br /> AOWIS aims to make capabilities that are traditionally distributed across expensive and proprietary engineering, GIS, SCADA, telemetry, and asset-management products available through an open and interoperable platform suitable for both small local installations and larger water systems.<br /> }}<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> {{Header box<br /> | title = Governance &amp; Legitimacy<br /> | color = turquoise<br /> | body = <br /> AOWIS includes a transparent governance model to ensure:<br /> <br /> * open participation <br /> * clear certification processes <br /> * stable versioning <br /> * long‑term protection of the standard <br /> <br /> See: [[Governance:Main_Page|Governance]].<br /> }}<br /> <br /> {{Header box<br /> | title = Navigation<br /> | color = grey<br /> | body =<br /> * [[AOWIS:Table_of_Contents|Table of Contents]] <br /> * [[Reference:Glossary|Glossary]] <br /> * [[Reference:FAQ|FAQ]] <br /> * [[Reference:Change_Log|Change Log]] <br /> <br /> * [https://github.com/aowis-org GitHub]<br /> }}<br /> &lt;/div&gt;<br /> <br /> {{Header box<br /> | title = Partners<br /> | color = indigo<br /> | body = <br /> [[File:Afriticgroup.webp|250px|frameless|center|link=https://afriticgroup.com/]]<br /> }}<br /> <br /> ''AOWIS is an open, evolving standard. Contributions are welcome. For contact, please visit us on [https://github.com/aowis-org GitHub]''</div>

Samuel https://aowis.org/index.php?title=Main_Page&diff=699 2026-09-05T14:28:26Z

<p>Samuel: </p> <hr /> <div>{{MainPageBanner}}<br /> <br /> {{Header box<br /> | title = Motivation<br /> | color = teal<br /> | body = <br /> <br /> [[File:Countryside.jpg|class=fullwidth|center]]<br /> <br /> In less developed regions, such as rural areas and small towns in Africa, water distribution remains a significant challenge. While NGOs have been successfully supporting communities for decades by drilling wells, installing pumps, and sometimes building water towers, distributing water across a network on the surface is often difficult.<br /> <br /> Local initiatives that take on these projects frequently encounter a situation where operating the system manually becomes unsustainable, requiring constant attention. Qualified personnel are scarce, and suitable technology to support automated or semi-automated operation is either unavailable under local constraints or too expensive.<br /> <br /> This is where AOWIS aims to contribute: by providing an open standard for designing, deploying, and managing water and agricultural infrastructure in such environments. AOWIS supports both the planning phase—helping initiatives evaluate and design systems based on regional conditions such as topography—and the operational phase, including system monitoring, control, and maintenance.<br /> <br /> In addition, AOWIS aims to support the training of local technicians and to collaborate closely with experienced NGOs and local initiatives that already operate and maintain such systems, in order to improve sustainability and reduce operational burden.<br /> }}<br /> <br /> {{Header box<br /> | title = Why an Open Standard is Needed<br /> | color = turquoise<br /> | body = <br /> <br /> [[File:Cooperation.jpg|400px|frameless|right]]<br /> <br /> In environments where infrastructure is built over decades by many different actors using solutions from different vendors and manufacturers, systems become fragmented, forcing operators to manage multiple incompatible tools and workflows while making daily operation, maintenance, expansion, and staff training increasingly complex and costly.<br /> <br /> This fragmentation often results in vendor lock-in, where systems depend on specific tools, expertise, or suppliers that may not remain available over the full lifecycle of the infrastructure.<br /> <br /> An open standard provides a shared technical foundation that enables interoperability and ensures systems can be maintained and extended independently of any single product or provider.<br /> <br /> AOWIS defines such a foundation for water and agricultural infrastructure under real-world operational constraints.<br /> }}<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> {{Header box<br /> | title = Operation Conditions of AOWIS<br /> | color = lightblue<br /> | body =<br /> [[File:Village.jpg|250px|frameless|right]]<br /> <br /> AOWIS is designed to operate under the real-world conditions faced by local initiatives. These include, among others:<br /> <br /> * unreliable power supply<br /> * intermittent connectivity<br /> * diverse or aging equipment<br /> * limited availability of trained personnel<br /> * the need for safety and autonomous operation<br /> <br /> AOWIS enables systems that continue to function safely and reliably, even under degraded or adverse conditions.<br /> }}<br /> <br /> {{Header box<br /> | title = Facing the Challenges<br /> | color = lightblue<br /> | body = <br /> AOWIS addresses these operational challenges through the following principles:<br /> <br /> * human-in-the-loop control<br /> * offline-first operation<br /> * safe fallback behavior<br /> * modular and extensible logic<br /> * shared infrastructure models<br /> * training programs for local operators<br /> * transparent governance<br /> <br /> The goal is to make essential systems '''robust, maintainable, and locally operable'''.<br /> }}<br /> &lt;/div&gt;<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> <br /> {{Header box<br /> | title = Start Here<br /> | color = yellow<br /> | body =<br /> If you are new to AOWIS, begin with:<br /> <br /> * [[Concepts:Design_Philosophy|Design Philosophy]] <br /> * [[Standard:Definitions|Definitions]] <br /> * [[Standard:Normative_Requirements|Normative Requirements]] <br /> * [[Modules:Module_Template|Module Template]] <br /> * [[AOWIS:Contributor_Guide_External|Contributor Guide - External]]<br /> * [[AOWIS:Contributor_Guide_Internal|Contributor Guide - Internal]]<br /> * [[AOWIS:Writing_Style_Guide|Writing Style Guide]]<br /> * [[AOWIS:AI_Usage_Guide|AI Usage Guide]]<br /> * [[AOWIS:Research_Form_Guide|Research Form Guide]]<br /> * [[AOWIS:Naming_Convention_Specification|Naming Convention Specification]]<br /> * [[AOWIS:Change_Log__Versioning|Change Log &amp; Versioning]]<br /> * [[AOWIS:Wiki|This Wiki]]<br /> <br /> These pages explain how to read, use, and contribute to the standard.<br /> }}<br /> <br /> {{Header box<br /> | title = List of Requirement Pages<br /> | color = brown<br /> | body = <br /> This index lists AOWIS pages that define normative requirements (MUST/SHOULD/MAY statements) and conformance rules.<br /> <br /> '''Dev Rules''' — specs for writing and maintaining AOWIS<br /> <br /> * '''REQ-AI:''' [[AOWIS:AI_Usage_Guide|AI Usage Guide]]<br /> <br /> '''Technical Standard''' — system behavior and data models<br /> <br /> * '''REQ-MEAS, REQ-MEAS-UI:''' [[Measurement:Units|Unit System Requirements]]<br /> * '''REQ-MEAS-UNI:''' [[Measurement:Unit_Identifiers|Unit Identifiers]]<br /> }}<br /> <br /> &lt;/div&gt;<br /> <br /> {{Header box<br /> | title = AOWIS Documentation Structure<br /> | color = purple<br /> | body = <br /> AOWIS documentation is organized into dedicated namespaces with clearly separated purposes.<br /> <br /> The [[Standard:Main_Page|Standard]] namespace contains the normative requirements that define AOWIS compliance. The other namespaces provide the motivation, concepts, engineering knowledge, architectures, operational models, implementation guidance, reference designs, training material, and supporting information needed to understand, implement, and operate AOWIS systems.<br /> <br /> * [[Motivation:Main_Page|Motivation]] – Causal justification of design requirements based on real-world failures, constraints, and operational realities.<br /> * [[Standard:Main_Page|Standard]] – The normative core of AOWIS. Defines requirements and definitions specifying what AOWIS-compliant systems MUST, SHOULD, or MAY do.<br /> * [[Concepts:Main_Page|Concepts]] – Core ideas, philosophy, rationale, and contextual understanding that explain AOWIS without prescribing a specific implementation.<br /> * [[Architecture:Main_Page|Architecture]] – High-level system structure, including controllers, layers, communication, data flows, and their interactions.<br /> * [[Infrastructure:Main_Page|Infrastructure]] – Physical technologies, systems, and components used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints.<br /> * [[Measurement:Main_Page|Measurement]] – Definition and handling of sensor data, manual measurements, calibration, uncertainty, and derived physical values.<br /> * [[Data:Main_Page|Data]] – Data models, schemas, logging structures, synchronization formats, and data lifecycle rules.<br /> * [[Operations:Main_Page|Operations]] – Runtime behavior, control logic, state transitions, fallback behavior, and decision-making during system operation.<br /> * [[Modules:Main_Page|Modules]] – Reusable functional extensions that provide domain-specific capabilities within AOWIS.<br /> * [[Reference:Main_Page|Reference]] – Non-normative concrete implementations, engineering blueprints, example deployments, and validated design patterns showing specific ways AOWIS systems may be built.<br /> * [[Databases:Main_Page|Databases]] – Federated knowledge bases and structured supporting information used by AOWIS implementations.<br /> * [[Governance:Main_Page|Governance]] – Certification, compliance, auditing, trust, licensing, versioning, and organizational governance.<br /> * [[Training:Main_Page|Training]] – Operator education, technical training, field guidance, documentation literacy, and capacity building.<br /> * [[External:Main_Page|External]] – External projects, standards, technologies, and systems that relate to or influence AOWIS.<br /> <br /> For a full overview, see the [[AOWIS:Table_of_Contents|Table of Contents]].<br /> }}<br /> <br /> {{Header box<br /> | title = Roadmap<br /> | color = grey<br /> | body =<br /> [[File:Boring.jpg|250px|frameless|right]]<br /> <br /> At this stage, AOWIS is in an early development and conceptualization phase. The following areas outline the current technical priorities:<br /> <br /> === Research ===<br /> * Decide which [[Architecture:Protocols:Main_Page|Wireless Protocols]] could or should be used for AOWIS.<br /> ** Result: The first iteration will be built with [[Architecture:Protocols:LoRa/LoRaWAN|LoRaWAN]] and [[Architecture:Protocols:MQTT|MQTT]]<br /> <br /> === Hardware ===<br /> * Develop sensors for measuring water levels in reservoirs.<br /> * Develop voltage monitoring to support sizing and management of solar battery systems.<br /> * Design mechanisms for emergency shutdown of electrical systems within milliseconds in case of overvoltage or critical faults.<br /> ** This should be done low-tech with regular electrician solutions.<br /> <br /> === Software ===<br /> * Begin conceptualization of the core controller.<br /> ** The controller must be capable of modeling and evaluating complex graphs representing water distribution networks in real time, enabling dynamic adaptation to changing conditions.<br /> }}<br /> <br /> &lt;div class=&quot;hbox-row&quot;&gt;<br /> {{Header box<br /> | title = Governance &amp; Legitimacy<br /> | color = turquoise<br /> | body = <br /> AOWIS includes a transparent governance model to ensure:<br /> <br /> * open participation <br /> * clear certification processes <br /> * stable versioning <br /> * long‑term protection of the standard <br /> <br /> See: [[Governance:Main_Page|Governance]].<br /> }}<br /> <br /> {{Header box<br /> | title = Navigation<br /> | color = grey<br /> | body =<br /> * [[AOWIS:Table_of_Contents|Table of Contents]] <br /> * [[Reference:Glossary|Glossary]] <br /> * [[Reference:FAQ|FAQ]] <br /> * [[Reference:Change_Log|Change Log]] <br /> <br /> * [https://github.com/aowis-org GitHub]<br /> }}<br /> &lt;/div&gt;<br /> <br /> {{Header box<br /> | title = Partners<br /> | color = indigo<br /> | body = <br /> [[File:Afriticgroup.webp|250px|frameless|center|link=https://afriticgroup.com/]]<br /> }}<br /> <br /> ''AOWIS is an open, evolving standard. Contributions are welcome. For contact, please visit us on [https://github.com/aowis-org GitHub]''</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=698 2026-09-05T14:25:05Z

<p>Samuel: </p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high-level structure of the AOWIS documentation. Each namespace serves a specific purpose within the overall AOWIS framework.<br /> <br /> The [[Standard:Main_Page|Standard]] namespace contains the normative core of AOWIS; the remaining namespaces provide supporting concepts, engineering knowledge, implementation guidance, operational models, reference designs, and related material.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference Implementations&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference Implementations: ==<br /> <br /> Concrete implementations, engineering blueprints, example deployments, and validated design patterns.<br /> <br /> Reference pages describe specific implementations of technologies, systems, and principles documented elsewhere in AOWIS. They are non-normative unless a normative AOWIS requirement explicitly references them.<br /> <br /> Contains:<br /> <br /> * Case studies<br /> * Implementation examples<br /> * Engineering blueprints<br /> * Hardware examples<br /> * Bills of materials<br /> * Construction details<br /> * Example deployments<br /> * Validated design patterns<br /> <br /> == TODO ==<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=697 2026-09-05T14:23:36Z

<p>Samuel: </p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high‑level structure of the AOWIS documentation. <br /> Each namespace serves a specific purpose within the overall architecture.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference Implementations&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference Implementations: ==<br /> <br /> Concrete implementations, engineering blueprints, example deployments, and validated design patterns.<br /> <br /> Reference pages describe specific implementations of technologies, systems, and principles documented elsewhere in AOWIS. They are non-normative unless a normative AOWIS requirement explicitly references them.<br /> <br /> Contains:<br /> <br /> * Case studies<br /> * Implementation examples<br /> * Engineering blueprints<br /> * Hardware examples<br /> * Bills of materials<br /> * Construction details<br /> * Example deployments<br /> * Validated design patterns<br /> <br /> == TODO ==<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=696 2026-09-05T14:22:29Z

<p>Samuel: /* Reference Implementations: */</p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high‑level structure of the AOWIS standard. <br /> Each namespace serves a specific purpose within the overall architecture.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference Implementations&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference Implementations: ==<br /> <br /> Concrete implementations, engineering blueprints, example deployments, and validated design patterns.<br /> <br /> Reference pages describe specific implementations of technologies, systems, and principles documented elsewhere in AOWIS. They are non-normative unless a normative AOWIS requirement explicitly references them.<br /> <br /> Contains:<br /> <br /> * Case studies<br /> * Implementation examples<br /> * Engineering blueprints<br /> * Hardware examples<br /> * Bills of materials<br /> * Construction details<br /> * Example deployments<br /> * Validated design patterns<br /> <br /> == TODO ==<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=Reference:Main_Page&diff=695 2026-09-05T14:14:33Z

<p>Samuel: </p> <hr /> <div>{{DISPLAYTITLE:Reference Implementations:Main Page}}<br /> <br /> Reference pages describe concrete implementations of technologies and principles documented elsewhere in AOWIS. They may specify dimensions, materials, component selections, construction details, bills of materials, operating parameters, and deployment assumptions.<br /> <br /> Reference implementations illustrate safe practical deployment patterns. They do not define additional normative requirements.<br /> <br /> == Normative Status ==<br /> <br /> Reference implementations are '''informative'''. Replication of specific physical designs is not required for compliance.<br /> <br /> Local engineering approval, regulatory compliance, and structural validation remain the responsibility of the deploying entity.<br /> <br /> == Infrastructure Blueprints ==<br /> <br /> Physical structures supporting water supply and control systems.<br /> <br /> * [[Reference:Water_Towers|Water Towers]]<br /> <br /> == Versioning ==<br /> <br /> Each reference implementation:<br /> <br /> * Is versioned independently<br /> * Specifies comptible AOWIS versions<br /> * Documents assumptions and constraints<br /> * Records revision history<br /> * May be revised or deprecated<br /> <br /> Exceptions to these are possible for particularly simple and/or low-tech solutions. Exceptions MUST be explained in the according '''Versioning''' section.<br /> <br /> [[Category:Reference Implementations]]</div>

Samuel https://aowis.org/index.php?title=Infrastructure:Main_Page&diff=694 2026-09-05T14:13:05Z

<p>Samuel: /* Infrastructure */</p> <hr /> <div>{{AI-Generated<br /> | tool=ChatGPT (GPT-5.6 Sol)<br /> | date=2026-09-05<br /> | scope=this page<br /> }}<br /> <br /> = Infrastructure =<br /> <br /> The '''Infrastructure''' domain covers the physical systems used to extract, treat, store, transport, distribute, and manage water and agricultural resources within AOWIS deployments.<br /> <br /> This includes pumps, wells, pipelines, valves, reservoirs, water treatment systems, energy systems, and other field hardware.<br /> <br /> Infrastructure pages describe classes of physical technologies, systems, and components. Specific construction blueprints, dimensioned designs, bills of materials, and example deployments belong under [[Reference:Main_Page|Reference Implementations]].<br /> <br /> Where applicable, infrastructure should be considered under the real-world operating conditions targeted by AOWIS, including limited technical resources, unreliable power supply, harsh environmental conditions, and the need for long-term local maintainability.<br /> <br /> <br /> == Water Sources ==<br /> <br /> Systems and structures used to obtain raw water.<br /> <br /> * [[Infrastructure:Wells|Wells]]<br /> * [[Infrastructure:Boreholes|Boreholes]]<br /> * [[Infrastructure:Surface Water|Surface Water]]<br /> * [[Infrastructure:Rainwater Harvesting|Rainwater Harvesting]]<br /> <br /> <br /> == Water Extraction and Pumping ==<br /> <br /> Equipment used to extract and move water.<br /> <br /> * [[Infrastructure:Pumps|Pumps]]<br /> * [[Infrastructure:Submersible Pumps|Submersible Pumps]]<br /> * [[Infrastructure:Surface Pumps|Surface Pumps]]<br /> * [[Infrastructure:Solar Pumping|Solar Pumping]]<br /> * [[Infrastructure:Manual Pumps|Manual Pumps]]<br /> <br /> <br /> == Water Treatment and Quality ==<br /> <br /> Physical systems used to improve raw water quality or make water suitable for its intended use.<br /> <br /> * [[Infrastructure:Water Treatment|Water Treatment]]<br /> ** [[Infrastructure:Desalination|Desalination]]<br /> *** [[Infrastructure:Solar Desalination|Solar Desalination]]<br /> ** [[Infrastructure:Filtration|Filtration]]<br /> ** [[Infrastructure:Disinfection|Disinfection]]<br /> ** [[Infrastructure:Remineralization|Remineralization]]<br /> <br /> Water-quality measurement, measurement procedures, units, calibration, and representation of measurement data belong primarily to the [[Measurement:Main_Page|Measurement]] domain.<br /> <br /> <br /> == Water Storage ==<br /> <br /> Systems used to store raw, treated, or distributed water.<br /> <br /> * [[Infrastructure:Water Storage|Water Storage]]<br /> * [[Infrastructure:Water Tanks|Water Tanks]]<br /> * [[Infrastructure:Reservoirs|Reservoirs]]<br /> * [[Infrastructure:Water Towers|Water Towers]]<br /> <br /> <br /> == Water Distribution ==<br /> <br /> Physical infrastructure used to transport and distribute water.<br /> <br /> * [[Infrastructure:Water Distribution|Water Distribution]]<br /> * [[Infrastructure:Pipelines|Pipelines]]<br /> * [[Infrastructure:Valves|Valves]]<br /> * [[Infrastructure:Pressure Management|Pressure Management]]<br /> * [[Infrastructure:Distribution Points|Distribution Points]]<br /> <br /> <br /> == Irrigation Infrastructure ==<br /> <br /> Physical systems used for agricultural water distribution.<br /> <br /> * [[Infrastructure:Irrigation|Irrigation]]<br /> * [[Infrastructure:Drip Irrigation|Drip Irrigation]]<br /> * [[Infrastructure:Irrigation Reservoirs|Irrigation Reservoirs]]<br /> * [[Infrastructure:Irrigation Distribution|Irrigation Distribution]]<br /> <br /> <br /> == Energy Infrastructure ==<br /> <br /> Physical energy systems supporting water and agricultural infrastructure.<br /> <br /> * [[Infrastructure:Energy Systems|Energy Systems]]<br /> * [[Infrastructure:Solar Power|Solar Power]]<br /> * [[Infrastructure:Battery Systems|Battery Systems]]<br /> * [[Infrastructure:Electrical Distribution|Electrical Distribution]]<br /> * [[Infrastructure:Backup Power|Backup Power]]<br /> <br /> <br /> == Field Hardware ==<br /> <br /> Physical components used to support monitoring, control, protection, and operation.<br /> <br /> * [[Infrastructure:Sensors|Sensors]]<br /> * [[Infrastructure:Actuators|Actuators]]<br /> * [[Infrastructure:Control Cabinets|Control Cabinets]]<br /> * [[Infrastructure:Electrical Protection|Electrical Protection]]<br /> * [[Infrastructure:Field Enclosures|Field Enclosures]]<br /> * [[Infrastructure:Cabling|Cabling]]<br /> <br /> <br /> == Design Considerations ==<br /> <br /> Infrastructure deployed within AOWIS environments may need to account for:<br /> <br /> * limited availability of replacement parts<br /> * limited access to specialist technicians<br /> * unreliable or intermittent electrical power<br /> * high temperatures and solar exposure<br /> * dust, sand, moisture, and corrosion<br /> * long transport distances and difficult logistics<br /> * compatibility with existing or aging infrastructure<br /> * ease of inspection and maintenance<br /> * safe operation under degraded conditions<br /> * local fabrication and repair capabilities<br /> <br /> These considerations describe the deployment context. Normative requirements, where applicable, belong in the [[Standard:Main_Page|Standard]] namespace.<br /> <br /> <br /> == Relationship to Other AOWIS Domains ==<br /> <br /> The Infrastructure domain describes '''physical systems and components'''.<br /> <br /> Related information may belong to other AOWIS domains:<br /> <br /> * [[Measurement:Main_Page|Measurement]] — measurement values, units, calibration, quality, and interpretation<br /> * [[Architecture:Main_Page|Architecture]] — system structure and interaction between major components<br /> * [[Operations:Main_Page|Operations]] — operational behavior, control logic, and runtime procedures<br /> * [[Modules:Main_Page|Modules]] — reusable functional capabilities<br /> * [[Reference:Main_Page|Reference]] — concrete example designs and reference implementations<br /> * [[Standard:Main_Page|Standard]] — normative AOWIS requirements<br /> <br /> <br /> == Reference Implementations ==<br /> <br /> Concrete engineering designs and deployment examples should generally be documented in the [[Reference:Main_Page|Reference]] namespace rather than here.<br /> <br /> Infrastructure pages describe technologies, components, design considerations, limitations, and interfaces.<br /> <br /> Reference pages may describe specific implementations such as:<br /> <br /> * water tower designs<br /> * pumping station layouts<br /> * solar pumping installations<br /> * low-tech water treatment systems<br /> * solar desalination installations<br /> * irrigation installations<br /> <br /> <br /> == See Also ==<br /> <br /> * [[Main_Page|AOWIS Main Page]]<br /> * [[AOWIS:Table_of_Contents|Table of Contents]]<br /> * [[Reference:Main_Page|Reference Implementations]]<br /> * [[Measurement:Main_Page|Measurement]]<br /> * [[Architecture:Main_Page|Architecture]]<br /> <br /> [[Category:Infrastructure]]<br /> [[Category:AOWIS]]</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=693 2026-09-05T13:55:21Z

<p>Samuel: /* Reference Implementations: */</p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high‑level structure of the AOWIS standard. <br /> Each namespace serves a specific purpose within the overall architecture.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference Implementations&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference Implementations: ==<br /> Concrete implementations, engineering blueprints, example deployments, and validated design patterns.<br /> <br /> Contains:<br /> * Case studies<br /> * Implementation examples<br /> * Hardware examples<br /> <br /> == TODO ==<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=Infrastructure:Main_Page&diff=692 2026-09-05T13:50:51Z

<p>Samuel: /* Infrastructure */</p> <hr /> <div>{{AI-Generated<br /> | tool=ChatGPT (GPT-5.6 Sol)<br /> | date=2026-09-05<br /> | scope=this page<br /> }}<br /> <br /> = Infrastructure =<br /> <br /> The '''Infrastructure''' domain covers the physical systems used to extract, treat, store, transport, distribute, and manage water and agricultural resources within AOWIS deployments.<br /> <br /> This includes pumps, wells, pipelines, valves, reservoirs, water treatment systems, energy systems, and other field hardware.<br /> <br /> Infrastructure documentation focuses on the physical characteristics, practical deployment, operation, maintenance, and interaction of these systems. Actual implementations should instead be documented at [[Reference:Main_Page|Reference Implementations]].<br /> <br /> Where applicable, infrastructure should be considered under the real-world operating conditions targeted by AOWIS, including limited technical resources, unreliable power supply, harsh environmental conditions, and the need for long-term local maintainability.<br /> <br /> <br /> == Water Sources ==<br /> <br /> Systems and structures used to obtain raw water.<br /> <br /> * [[Infrastructure:Wells|Wells]]<br /> * [[Infrastructure:Boreholes|Boreholes]]<br /> * [[Infrastructure:Surface Water|Surface Water]]<br /> * [[Infrastructure:Rainwater Harvesting|Rainwater Harvesting]]<br /> <br /> <br /> == Water Extraction and Pumping ==<br /> <br /> Equipment used to extract and move water.<br /> <br /> * [[Infrastructure:Pumps|Pumps]]<br /> * [[Infrastructure:Submersible Pumps|Submersible Pumps]]<br /> * [[Infrastructure:Surface Pumps|Surface Pumps]]<br /> * [[Infrastructure:Solar Pumping|Solar Pumping]]<br /> * [[Infrastructure:Manual Pumps|Manual Pumps]]<br /> <br /> <br /> == Water Treatment and Quality ==<br /> <br /> Physical systems used to improve raw water quality or make water suitable for its intended use.<br /> <br /> * [[Infrastructure:Water Treatment|Water Treatment]]<br /> ** [[Infrastructure:Desalination|Desalination]]<br /> *** [[Infrastructure:Solar Desalination|Solar Desalination]]<br /> ** [[Infrastructure:Filtration|Filtration]]<br /> ** [[Infrastructure:Disinfection|Disinfection]]<br /> ** [[Infrastructure:Remineralization|Remineralization]]<br /> <br /> Water-quality measurement, measurement procedures, units, calibration, and representation of measurement data belong primarily to the [[Measurement:Main_Page|Measurement]] domain.<br /> <br /> <br /> == Water Storage ==<br /> <br /> Systems used to store raw, treated, or distributed water.<br /> <br /> * [[Infrastructure:Water Storage|Water Storage]]<br /> * [[Infrastructure:Water Tanks|Water Tanks]]<br /> * [[Infrastructure:Reservoirs|Reservoirs]]<br /> * [[Infrastructure:Water Towers|Water Towers]]<br /> <br /> <br /> == Water Distribution ==<br /> <br /> Physical infrastructure used to transport and distribute water.<br /> <br /> * [[Infrastructure:Water Distribution|Water Distribution]]<br /> * [[Infrastructure:Pipelines|Pipelines]]<br /> * [[Infrastructure:Valves|Valves]]<br /> * [[Infrastructure:Pressure Management|Pressure Management]]<br /> * [[Infrastructure:Distribution Points|Distribution Points]]<br /> <br /> <br /> == Irrigation Infrastructure ==<br /> <br /> Physical systems used for agricultural water distribution.<br /> <br /> * [[Infrastructure:Irrigation|Irrigation]]<br /> * [[Infrastructure:Drip Irrigation|Drip Irrigation]]<br /> * [[Infrastructure:Irrigation Reservoirs|Irrigation Reservoirs]]<br /> * [[Infrastructure:Irrigation Distribution|Irrigation Distribution]]<br /> <br /> <br /> == Energy Infrastructure ==<br /> <br /> Physical energy systems supporting water and agricultural infrastructure.<br /> <br /> * [[Infrastructure:Energy Systems|Energy Systems]]<br /> * [[Infrastructure:Solar Power|Solar Power]]<br /> * [[Infrastructure:Battery Systems|Battery Systems]]<br /> * [[Infrastructure:Electrical Distribution|Electrical Distribution]]<br /> * [[Infrastructure:Backup Power|Backup Power]]<br /> <br /> <br /> == Field Hardware ==<br /> <br /> Physical components used to support monitoring, control, protection, and operation.<br /> <br /> * [[Infrastructure:Sensors|Sensors]]<br /> * [[Infrastructure:Actuators|Actuators]]<br /> * [[Infrastructure:Control Cabinets|Control Cabinets]]<br /> * [[Infrastructure:Electrical Protection|Electrical Protection]]<br /> * [[Infrastructure:Field Enclosures|Field Enclosures]]<br /> * [[Infrastructure:Cabling|Cabling]]<br /> <br /> <br /> == Design Considerations ==<br /> <br /> Infrastructure deployed within AOWIS environments may need to account for:<br /> <br /> * limited availability of replacement parts<br /> * limited access to specialist technicians<br /> * unreliable or intermittent electrical power<br /> * high temperatures and solar exposure<br /> * dust, sand, moisture, and corrosion<br /> * long transport distances and difficult logistics<br /> * compatibility with existing or aging infrastructure<br /> * ease of inspection and maintenance<br /> * safe operation under degraded conditions<br /> * local fabrication and repair capabilities<br /> <br /> These considerations describe the deployment context. Normative requirements, where applicable, belong in the [[Standard:Main_Page|Standard]] namespace.<br /> <br /> <br /> == Relationship to Other AOWIS Domains ==<br /> <br /> The Infrastructure domain describes '''physical systems and components'''.<br /> <br /> Related information may belong to other AOWIS domains:<br /> <br /> * [[Measurement:Main_Page|Measurement]] — measurement values, units, calibration, quality, and interpretation<br /> * [[Architecture:Main_Page|Architecture]] — system structure and interaction between major components<br /> * [[Operations:Main_Page|Operations]] — operational behavior, control logic, and runtime procedures<br /> * [[Modules:Main_Page|Modules]] — reusable functional capabilities<br /> * [[Reference:Main_Page|Reference]] — concrete example designs and reference implementations<br /> * [[Standard:Main_Page|Standard]] — normative AOWIS requirements<br /> <br /> <br /> == Reference Implementations ==<br /> <br /> Concrete engineering designs and deployment examples should generally be documented in the [[Reference:Main_Page|Reference]] namespace rather than here.<br /> <br /> Infrastructure pages describe technologies, components, design considerations, limitations, and interfaces.<br /> <br /> Reference pages may describe specific implementations such as:<br /> <br /> * water tower designs<br /> * pumping station layouts<br /> * solar pumping installations<br /> * low-tech water treatment systems<br /> * solar desalination installations<br /> * irrigation installations<br /> <br /> <br /> == See Also ==<br /> <br /> * [[Main_Page|AOWIS Main Page]]<br /> * [[AOWIS:Table_of_Contents|Table of Contents]]<br /> * [[Reference:Main_Page|Reference Implementations]]<br /> * [[Measurement:Main_Page|Measurement]]<br /> * [[Architecture:Main_Page|Architecture]]<br /> <br /> [[Category:Infrastructure]]<br /> [[Category:AOWIS]]</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=691 2026-09-05T13:48:25Z

<p>Samuel: /* Reference Implementations: */</p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high‑level structure of the AOWIS standard. <br /> Each namespace serves a specific purpose within the overall architecture.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference Implementations&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference Implementations: ==<br /> Non‑normative supporting material.<br /> <br /> Contains:<br /> * Case studies<br /> * Implementation examples<br /> * Hardware examples<br /> <br /> == TODO ==<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=690 2026-09-05T13:45:53Z

<p>Samuel: /* Infrastructure: */</p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high‑level structure of the AOWIS standard. <br /> Each namespace serves a specific purpose within the overall architecture.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference Implementations&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference Implementations: ==<br /> Non‑normative supporting material.<br /> <br /> Contains:<br /> * Case studies<br /> * Implementation examples<br /> * Hardware examples<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=689 2026-09-05T13:45:32Z

<p>Samuel: /* Reference: */</p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high‑level structure of the AOWIS standard. <br /> Each namespace serves a specific purpose within the overall architecture.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference Implementations: ==<br /> Non‑normative supporting material.<br /> <br /> Contains:<br /> * Case studies<br /> * Implementation examples<br /> * Hardware examples<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=688 2026-09-05T13:43:30Z

<p>Samuel: /* Infrastructure: */</p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high‑level structure of the AOWIS standard. <br /> Each namespace serves a specific purpose within the overall architecture.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference: ==<br /> Non‑normative supporting material.<br /> <br /> Contains:<br /> * Case studies<br /> * Implementation examples<br /> * Hardware examples<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=AOWIS:Table_of_Contents&diff=687 2026-09-05T13:42:59Z

<p>Samuel: /* Infrastructure: */</p> <hr /> <div><br /> ''Overview of all AOWIS namespaces and their intended scope.''<br /> <br /> This document defines the high‑level structure of the AOWIS standard. <br /> Each namespace serves a specific purpose within the overall architecture.<br /> <br /> ----<br /> <br /> == Standard: ==<br /> The normative core of AOWIS. <br /> Contains binding requirements, definitions, and compliance rules.<br /> <br /> Pages in this namespace include:<br /> * Scope of the standard<br /> * Normative requirements (MUST/SHOULD/MAY)<br /> * Definitions and terminology<br /> * Safety rules<br /> * Conformance levels<br /> * Versioning and change control<br /> <br /> ----<br /> <br /> == Concepts: ==<br /> Non‑normative explanations of the ideas behind AOWIS. <br /> Provides context, philosophy, and rationale.<br /> <br /> Typical content:<br /> * Design philosophy<br /> * Human‑in‑the‑loop principles<br /> * Offline‑first operation<br /> * Real‑world constraints<br /> * Paper‑based operation<br /> * Shared infrastructure model<br /> <br /> ----<br /> <br /> == Architecture: ==<br /> The structural blueprint of AOWIS. <br /> Describes how controllers, communication, and logic fit together.<br /> <br /> Includes:<br /> * System overview<br /> * Field Controller architecture<br /> * Farm Controller architecture<br /> * HQ Controller architecture<br /> * Communication model<br /> * Data flow diagrams<br /> * Security model<br /> * State machines<br /> <br /> ----<br /> <br /> == Infrastructure: ==<br /> Physical technologies, systems, components, and engineering principles used in AOWIS deployments. Infrastructure pages describe classes of physical systems rather than specific implementation blueprints. Specific implementation blueprints go to &quot;Reference Implementations&quot; instead.<br /> <br /> Topics include:<br /> * Hydraulics<br /> * Pumps and pump protection<br /> * Valves and actuators<br /> * Water towers and tanks<br /> * Distribution networks<br /> * Electrical systems<br /> * Power constraints<br /> <br /> ----<br /> <br /> == Measurement: ==<br /> All forms of measurement used by AOWIS, including sensors, manual readings, and derived values.<br /> <br /> Sub‑topics:<br /> * Electronic sensors (soil moisture, flow meters, tank levels, weather, optical, power)<br /> * Manual measurements (dipsticks, visual inspection, paper forms)<br /> * Derived measurements (ET₀, flow estimation, soil water balance)<br /> * Calibration and drift<br /> * Measurement uncertainty<br /> <br /> ----<br /> <br /> == Data: ==<br /> Data structures, logs, synchronization formats, and documentation models.<br /> <br /> Includes:<br /> * Data models<br /> * Logging formats<br /> * Paper forms<br /> * Sync protocols<br /> * Event types<br /> * Audit trails<br /> * Data validation rules<br /> <br /> ----<br /> <br /> == Operations: ==<br /> Runtime behavior and operational logic of AOWIS.<br /> <br /> Covers:<br /> * Decision hierarchy<br /> * Scheduling<br /> * Safety logic<br /> * Manual intervention<br /> * Bypass modes<br /> * Fallback behavior<br /> * Offline operation<br /> <br /> ----<br /> <br /> == Modules: ==<br /> Domain‑specific extensions to the AOWIS core. <br /> Modules define specialized logic for particular use cases.<br /> <br /> Examples:<br /> * Crop irrigation<br /> * Community water supply<br /> * Livestock<br /> * Poultry<br /> * Greenhouse and hydroponics<br /> * Custom modules<br /> * Module templates<br /> <br /> ----<br /> <br /> == Databases: ==<br /> Federated knowledge bases that support AOWIS implementations.<br /> <br /> Includes:<br /> * AOWIS‑Agro‑DB<br /> * AOWIS‑Water‑DB<br /> * Hardware database<br /> * Device database<br /> * Contribution model<br /> * Sync model<br /> <br /> ----<br /> <br /> == Governance: ==<br /> Organizational, legal, and certification aspects of AOWIS.<br /> <br /> Topics:<br /> * Certification processes<br /> * Compliance verification<br /> * Licensing<br /> * Governance model<br /> * Protection strategy<br /> <br /> ----<br /> <br /> == Training: ==<br /> Human capacity building and operator education.<br /> <br /> Includes:<br /> * Training programs<br /> * Certification levels<br /> * Curriculum<br /> * Field guides<br /> * Operator checklists<br /> <br /> ----<br /> <br /> == Reference: ==<br /> Non‑normative supporting material.<br /> <br /> Contains:<br /> * Case studies<br /> * Implementation examples<br /> * Hardware examples<br /> * Glossary<br /> * FAQ<br /> * Change log<br /> <br /> ----<br /> <br /> ''End of AOWIS Table of Contents''</div>

Samuel https://aowis.org/index.php?title=Infrastructure:Main_Page&diff=686 2026-09-05T13:16:51Z

<p>Samuel: Created page with &quot;{{AI-Generated | tool=ChatGPT (GPT-5.6 Sol) | date=2026-09-05 | scope=this page }} = Infrastructure = The &#039;&#039;&#039;Infrastructure&#039;&#039;&#039; domain covers the physical systems used to extract, treat, store, transport, distribute, and manage water and agricultural resources within AOWIS deployments. This includes pumps, wells, pipelines, valves, reservoirs, water treatment systems, energy systems, and other field hardware. Infrastructure documentation focuses on the physical cha...&quot;</p> <hr /> <div>{{AI-Generated<br /> | tool=ChatGPT (GPT-5.6 Sol)<br /> | date=2026-09-05<br /> | scope=this page<br /> }}<br /> <br /> = Infrastructure =<br /> <br /> The '''Infrastructure''' domain covers the physical systems used to extract, treat, store, transport, distribute, and manage water and agricultural resources within AOWIS deployments.<br /> <br /> This includes pumps, wells, pipelines, valves, reservoirs, water treatment systems, energy systems, and other field hardware.<br /> <br /> Infrastructure documentation focuses on the physical characteristics, practical deployment, operation, maintenance, and interaction of these systems.<br /> <br /> Where applicable, infrastructure should be considered under the real-world operating conditions targeted by AOWIS, including limited technical resources, unreliable power supply, harsh environmental conditions, and the need for long-term local maintainability.<br /> <br /> <br /> == Water Sources ==<br /> <br /> Systems and structures used to obtain raw water.<br /> <br /> * [[Infrastructure:Wells|Wells]]<br /> * [[Infrastructure:Boreholes|Boreholes]]<br /> * [[Infrastructure:Surface Water|Surface Water]]<br /> * [[Infrastructure:Rainwater Harvesting|Rainwater Harvesting]]<br /> <br /> <br /> == Water Extraction and Pumping ==<br /> <br /> Equipment used to extract and move water.<br /> <br /> * [[Infrastructure:Pumps|Pumps]]<br /> * [[Infrastructure:Submersible Pumps|Submersible Pumps]]<br /> * [[Infrastructure:Surface Pumps|Surface Pumps]]<br /> * [[Infrastructure:Solar Pumping|Solar Pumping]]<br /> * [[Infrastructure:Manual Pumps|Manual Pumps]]<br /> <br /> <br /> == Water Treatment and Quality ==<br /> <br /> Physical systems used to improve raw water quality or make water suitable for its intended use.<br /> <br /> * [[Infrastructure:Water Treatment|Water Treatment]]<br /> ** [[Infrastructure:Desalination|Desalination]]<br /> *** [[Infrastructure:Solar Desalination|Solar Desalination]]<br /> ** [[Infrastructure:Filtration|Filtration]]<br /> ** [[Infrastructure:Disinfection|Disinfection]]<br /> ** [[Infrastructure:Remineralization|Remineralization]]<br /> <br /> Water-quality measurement, measurement procedures, units, calibration, and representation of measurement data belong primarily to the [[Measurement:Main_Page|Measurement]] domain.<br /> <br /> <br /> == Water Storage ==<br /> <br /> Systems used to store raw, treated, or distributed water.<br /> <br /> * [[Infrastructure:Water Storage|Water Storage]]<br /> * [[Infrastructure:Water Tanks|Water Tanks]]<br /> * [[Infrastructure:Reservoirs|Reservoirs]]<br /> * [[Infrastructure:Water Towers|Water Towers]]<br /> <br /> <br /> == Water Distribution ==<br /> <br /> Physical infrastructure used to transport and distribute water.<br /> <br /> * [[Infrastructure:Water Distribution|Water Distribution]]<br /> * [[Infrastructure:Pipelines|Pipelines]]<br /> * [[Infrastructure:Valves|Valves]]<br /> * [[Infrastructure:Pressure Management|Pressure Management]]<br /> * [[Infrastructure:Distribution Points|Distribution Points]]<br /> <br /> <br /> == Irrigation Infrastructure ==<br /> <br /> Physical systems used for agricultural water distribution.<br /> <br /> * [[Infrastructure:Irrigation|Irrigation]]<br /> * [[Infrastructure:Drip Irrigation|Drip Irrigation]]<br /> * [[Infrastructure:Irrigation Reservoirs|Irrigation Reservoirs]]<br /> * [[Infrastructure:Irrigation Distribution|Irrigation Distribution]]<br /> <br /> <br /> == Energy Infrastructure ==<br /> <br /> Physical energy systems supporting water and agricultural infrastructure.<br /> <br /> * [[Infrastructure:Energy Systems|Energy Systems]]<br /> * [[Infrastructure:Solar Power|Solar Power]]<br /> * [[Infrastructure:Battery Systems|Battery Systems]]<br /> * [[Infrastructure:Electrical Distribution|Electrical Distribution]]<br /> * [[Infrastructure:Backup Power|Backup Power]]<br /> <br /> <br /> == Field Hardware ==<br /> <br /> Physical components used to support monitoring, control, protection, and operation.<br /> <br /> * [[Infrastructure:Sensors|Sensors]]<br /> * [[Infrastructure:Actuators|Actuators]]<br /> * [[Infrastructure:Control Cabinets|Control Cabinets]]<br /> * [[Infrastructure:Electrical Protection|Electrical Protection]]<br /> * [[Infrastructure:Field Enclosures|Field Enclosures]]<br /> * [[Infrastructure:Cabling|Cabling]]<br /> <br /> <br /> == Design Considerations ==<br /> <br /> Infrastructure deployed within AOWIS environments may need to account for:<br /> <br /> * limited availability of replacement parts<br /> * limited access to specialist technicians<br /> * unreliable or intermittent electrical power<br /> * high temperatures and solar exposure<br /> * dust, sand, moisture, and corrosion<br /> * long transport distances and difficult logistics<br /> * compatibility with existing or aging infrastructure<br /> * ease of inspection and maintenance<br /> * safe operation under degraded conditions<br /> * local fabrication and repair capabilities<br /> <br /> These considerations describe the deployment context. Normative requirements, where applicable, belong in the [[Standard:Main_Page|Standard]] namespace.<br /> <br /> <br /> == Relationship to Other AOWIS Domains ==<br /> <br /> The Infrastructure domain describes '''physical systems and components'''.<br /> <br /> Related information may belong to other AOWIS domains:<br /> <br /> * [[Measurement:Main_Page|Measurement]] — measurement values, units, calibration, quality, and interpretation<br /> * [[Architecture:Main_Page|Architecture]] — system structure and interaction between major components<br /> * [[Operations:Main_Page|Operations]] — operational behavior, control logic, and runtime procedures<br /> * [[Modules:Main_Page|Modules]] — reusable functional capabilities<br /> * [[Reference:Main_Page|Reference]] — concrete example designs and reference implementations<br /> * [[Standard:Main_Page|Standard]] — normative AOWIS requirements<br /> <br /> <br /> == Reference Implementations ==<br /> <br /> Concrete engineering designs and deployment examples should generally be documented in the [[Reference:Main_Page|Reference]] namespace rather than here.<br /> <br /> Infrastructure pages describe technologies, components, design considerations, limitations, and interfaces.<br /> <br /> Reference pages may describe specific implementations such as:<br /> <br /> * water tower designs<br /> * pumping station layouts<br /> * solar pumping installations<br /> * low-tech water treatment systems<br /> * solar desalination installations<br /> * irrigation installations<br /> <br /> <br /> == See Also ==<br /> <br /> * [[Main_Page|AOWIS Main Page]]<br /> * [[AOWIS:Table_of_Contents|Table of Contents]]<br /> * [[Reference:Main_Page|Reference Implementations]]<br /> * [[Measurement:Main_Page|Measurement]]<br /> * [[Architecture:Main_Page|Architecture]]<br /> <br /> [[Category:Infrastructure]]<br /> [[Category:AOWIS]]</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=685 2026-08-19T11:12:37Z

<p>Samuel: </p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> This page is the normative registry of canonical measurement quantities and units used by AOWIS.<br /> <br /> The representation and conversion rules governing these quantities are defined in [[Measurement:Units]].<br /> <br /> UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is used for machine-readable physical unit identifiers.<br /> <br /> == Identifier and Field-Naming Rules ==<br /> <br /> The canonical unit assigned to each measurement quantity in this registry is authoritative.<br /> <br /> When a unit identifier is explicitly represented, it MUST use the canonical UCUM identifier defined here.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe naming convention used for fixed-schema field names, property names, database columns, and similar technical identifiers.<br /> <br /> The suffix convention is:<br /> <br /> * division is represented by &lt;code&gt;_per_&lt;/code&gt;;<br /> * multiplication is represented by &lt;code&gt;_&lt;/code&gt;;<br /> * unit symbols are normalized to lower case where required for identifier naming;<br /> * quantity-specific semantic qualifiers MAY be included where a literal unit-only suffix would be ambiguous;<br /> * dimensionless fields with canonical UCUM unit &lt;code&gt;1&lt;/code&gt; normally omit a unit suffix.<br /> <br /> For example:<br /> <br /> &lt;pre&gt;<br /> m3/h -&gt; m3_per_h<br /> m/s -&gt; m_per_s<br /> kW.h/m3 -&gt; kw_h_per_m3<br /> mm2/(100.m) -&gt; mm2_per_100m<br /> &lt;/pre&gt;<br /> <br /> The AOWIS identifier suffix is not itself a UCUM unit identifier.<br /> <br /> For generic or dynamically typed measurement values, the resolved measurement quantity determines the canonical unit through this registry.<br /> <br /> == Length and Distance Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |-<br /> | &lt;code&gt;darcy_weisbach_roughness_height&lt;/code&gt; || Absolute pipe-wall roughness height used by the Darcy-Weisbach formulation || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET Darcy-Weisbach pipe roughness<br /> |}<br /> <br /> == Geographic Coordinate Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Projected-coordinate easting<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Projected-coordinate northing<br /> |-<br /> | &lt;code&gt;local_x&lt;/code&gt; || X coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local coordinates when the coordinate system is defined in metres<br /> |-<br /> | &lt;code&gt;local_y&lt;/code&gt; || Y coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local coordinates when the coordinate system is defined in metres<br /> |}<br /> <br /> == Area and Volume Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> == Flow and Transport Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> == Hydraulic Head, Pressure, and Stress Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis<br /> |}<br /> <br /> == Time Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration and time steps<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time and clock-time controls<br /> |}<br /> <br /> == Hydraulic Coefficients and Other Dimensionless Quantities ==<br /> <br /> The canonical UCUM unit identifier for all quantities in this section is &lt;code&gt;1&lt;/code&gt;. The AOWIS unit suffix is omitted.<br /> <br /> Semantic terms such as &lt;code&gt;ratio&lt;/code&gt;, &lt;code&gt;factor&lt;/code&gt;, &lt;code&gt;coefficient&lt;/code&gt;, &lt;code&gt;multiplier&lt;/code&gt;, and &lt;code&gt;exponent&lt;/code&gt; describe the quantity and are not unit suffixes.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hazen_williams_roughness_coefficient&lt;/code&gt; || Hazen-Williams pipe roughness coefficient || &lt;code&gt;1&lt;/code&gt; || none || EPANET Hazen-Williams roughness<br /> |-<br /> | &lt;code&gt;chezy_manning_roughness_coefficient&lt;/code&gt; || Chezy-Manning pipe roughness coefficient || &lt;code&gt;1&lt;/code&gt; || none || EPANET Chezy-Manning roughness<br /> |-<br /> | &lt;code&gt;minor_loss_coefficient&lt;/code&gt; || Coefficient representing local hydraulic losses || &lt;code&gt;1&lt;/code&gt; || none || Pipe and valve minor loss; TCV setting<br /> |-<br /> | &lt;code&gt;darcy_weisbach_friction_factor&lt;/code&gt; || Darcy-Weisbach friction factor || &lt;code&gt;1&lt;/code&gt; || none || Pipe simulation result<br /> |-<br /> | &lt;code&gt;pump_speed_ratio&lt;/code&gt; || Pump rotational speed relative to nominal or reference speed || &lt;code&gt;1&lt;/code&gt; || none || Pump setting, result, pattern, control, and rule values<br /> |-<br /> | &lt;code&gt;pattern_multiplier&lt;/code&gt; || Factor applied by a hydraulic or energy pattern || &lt;code&gt;1&lt;/code&gt; || none || EPANET pattern factor<br /> |-<br /> | &lt;code&gt;demand_multiplier&lt;/code&gt; || Global factor applied to base demands || &lt;code&gt;1&lt;/code&gt; || none || EPANET demand multiplier<br /> |-<br /> | &lt;code&gt;pressure_exponent&lt;/code&gt; || Exponent used by the pressure-driven demand relation || &lt;code&gt;1&lt;/code&gt; || none || EPANET pressure exponent<br /> |-<br /> | &lt;code&gt;emitter_exponent&lt;/code&gt; || Exponent used by the emitter pressure-flow relation || &lt;code&gt;1&lt;/code&gt; || none || EPANET emitter exponent<br /> |-<br /> | &lt;code&gt;reaction_order&lt;/code&gt; || Order of a bulk, wall, or tank reaction equation || &lt;code&gt;1&lt;/code&gt; || none || EPANET reaction order<br /> |-<br /> | &lt;code&gt;specific_gravity&lt;/code&gt; || Fluid density relative to a defined reference density || &lt;code&gt;1&lt;/code&gt; || none || EPANET specific gravity<br /> |-<br /> | &lt;code&gt;relative_viscosity&lt;/code&gt; || Kinematic viscosity relative to the solver reference || &lt;code&gt;1&lt;/code&gt; || none || EPANET relative viscosity<br /> |-<br /> | &lt;code&gt;relative_diffusivity&lt;/code&gt; || Molecular diffusivity relative to the solver reference || &lt;code&gt;1&lt;/code&gt; || none || EPANET relative diffusivity<br /> |-<br /> | &lt;code&gt;mixing_fraction&lt;/code&gt; || Fraction of tank volume assigned to the applicable mixing zone || &lt;code&gt;1&lt;/code&gt; || none || EPANET tank mixing fraction<br /> |-<br /> | &lt;code&gt;hydraulic_accuracy&lt;/code&gt; || Relative hydraulic convergence criterion || &lt;code&gt;1&lt;/code&gt; || none || EPANET hydraulic accuracy<br /> |-<br /> | &lt;code&gt;hydraulic_damping_limit&lt;/code&gt; || Relative threshold controlling solver damping or status checks || &lt;code&gt;1&lt;/code&gt; || none || EPANET damping limit<br /> |-<br /> | &lt;code&gt;relative_error&lt;/code&gt; || Relative numerical error || &lt;code&gt;1&lt;/code&gt; || none || Hydraulic simulation statistics<br /> |-<br /> | &lt;code&gt;flow_balance_ratio&lt;/code&gt; || Ratio of total outflow to total inflow || &lt;code&gt;1&lt;/code&gt; || none || EPANET flow-balance reporting<br /> |-<br /> | &lt;code&gt;quality_mass_balance_ratio&lt;/code&gt; || Water-quality mass-conservation ratio || &lt;code&gt;1&lt;/code&gt; || none || EPANET quality mass-balance reporting<br /> |}<br /> <br /> == Percentage Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |-<br /> | &lt;code&gt;operating_time_percentage&lt;/code&gt; || Fraction of a reporting period during which equipment operates || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump energy reporting<br /> |-<br /> | &lt;code&gt;demand_reduction_percentage&lt;/code&gt; || Reduction in delivered demand relative to requested demand || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Hydraulic statistics<br /> |-<br /> | &lt;code&gt;leakage_loss_percentage&lt;/code&gt; || Leakage loss relative to total system inflow || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Leakage statistics<br /> |}<br /> <br /> == Reaction and Leakage Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe, and tank first-order bulk reactions<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe first-order wall reactions<br /> |-<br /> | &lt;code&gt;leak_area_per_100m_pipe_length&lt;/code&gt; || Effective leak area assigned per 100 metres of pipe length || square millimetre per 100 metres (mm²/100 m) || &lt;code&gt;mm2/(100.m)&lt;/code&gt; || &lt;code&gt;mm2_per_100m&lt;/code&gt; || EPANET 2.3 FAVAD leak area; EPANET uses 100 project length units and the adapter converts when required&lt;ref name=&quot;EPANET23&quot;&gt;OWA-EPANET 2.3 release notes https://github.com/OpenWaterAnalytics/EPANET/blob/v2.3/ReleaseNotes2_3.md&lt;/ref&gt;<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre of pressure head (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m_head&lt;/code&gt; || EPANET 2.3 FAVAD leak expansion<br /> |}<br /> <br /> == Water Quality Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || Chemical quality input and results<br /> |-<br /> | &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt; || Chemical mass introduced into or transported through the system per unit time || milligram per minute (mg/min) || &lt;code&gt;mg/min&lt;/code&gt; || &lt;code&gt;mg_per_min&lt;/code&gt; || EPANET mass-booster source strength and source mass rate<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> == Power, Energy, and Electrical Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> <br /> == Context-Dependent Quantity Resolution ==<br /> <br /> Some Model concepts resolve to different registered measurement quantities depending on their context. The representation requirements for such values are defined in [[Measurement:Units]] and, where applicable, the corresponding Measurement subsystem specification.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Model Concept !! Resolved Measurement Quantity<br /> |-<br /> | Valve setting || PRV, PSV, and PBV: &lt;code&gt;pressure_head&lt;/code&gt;; FCV: &lt;code&gt;volumetric_flow_rate&lt;/code&gt;; TCV: &lt;code&gt;minor_loss_coefficient&lt;/code&gt;; PCV: &lt;code&gt;valve_position&lt;/code&gt;; GPV: curve reference rather than a measurement value<br /> |-<br /> | Pump setting || &lt;code&gt;pump_speed_ratio&lt;/code&gt;<br /> |-<br /> | Control trigger || &lt;code&gt;water_level&lt;/code&gt;, &lt;code&gt;pressure_head&lt;/code&gt;, &lt;code&gt;elapsed_time&lt;/code&gt;, or &lt;code&gt;time_of_day&lt;/code&gt;, depending on control type<br /> |-<br /> | Control or rule action setting || The measurement quantity supported by the target link type<br /> |-<br /> | Rule premise value || The measurement quantity selected by the rule variable<br /> |-<br /> | Initial or simulated quality || &lt;code&gt;chemical_concentration&lt;/code&gt;, &lt;code&gt;water_age&lt;/code&gt;, or &lt;code&gt;source_trace_percentage&lt;/code&gt;, depending on quality-analysis mode<br /> |-<br /> | Quality-source strength || &lt;code&gt;chemical_concentration&lt;/code&gt; or &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt;, depending on source type<br /> |-<br /> | Reaction coefficient || The applicable reaction-coefficient quantity determined by reaction order<br /> |-<br /> | Emitter coefficient || Equation-dependent coefficient in &lt;code&gt;Q = C H^n&lt;/code&gt;; no single fixed canonical unit applies independently of &lt;code&gt;n&lt;/code&gt;<br /> |-<br /> | Generic curve coordinate || The measurement quantity defined by the curve type<br /> |-<br /> | Report threshold || The measurement quantity of the corresponding report field<br /> |-<br /> | EPANET map or backdrop coordinate || The applicable geographic, projected, or local coordinate quantity after the coordinate representation is resolved<br /> |}<br /> <br /> == References ==<br /> <br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Main_Page&diff=684 2026-08-19T11:12:16Z

<p>Samuel: </p> <hr /> <div>= Measurement =<br /> <br /> Measurements are fundamental to AOWIS operations. Decisions in monitoring, control, maintenance, planning, safety, and research depend on reliable measurement data.<br /> <br /> This Domain defines how AOWIS represents, records, exchanges, validates, and interprets measurements across water, agricultural, environmental, and infrastructure systems.<br /> <br /> == Core Specifications ==<br /> <br /> * [[Measurement:Units|Unit System Requirements]]<br /> * [[Measurement:Canonical_Units|Canonical Units]]<br /> <br /> == Subsystems ==<br /> <br /> * [[Measurement:Elevation|Elevation]]<br /> * [[Measurement:Time]]<br /> * [[Measurement:Quality]]<br /> * [[Measurement:Calibration]]<br /> <br /> == Supporting Concepts ==<br /> <br /> * Measurement sources<br /> * Data validation<br /> * Uncertainty handling<br /> * Storage &amp; exchange rules<br /> <br /> == Hardware ==<br /> <br /> * [[Measurement:Pressure_Sensor_Examples|Pressure sensor examples]]</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=683 2026-08-19T11:11:55Z

<p>Samuel: </p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Canonical_Units]]<br /> <br /> AOWIS uses a canonical representation for measurement quantities. Each measurement quantity has one canonical unit defined in [[Measurement:Canonical_Units|Canonical Units]].<br /> <br /> Canonical units are selected individually based on SI, established engineering practice, numerical practicality, and interoperability. Values MAY use other units at system boundaries and in user interfaces, but the authoritative AOWIS representation remains canonical.<br /> <br /> == Purpose ==<br /> <br /> This specification defines the AOWIS unit system for measurement quantities, including canonical representation, unit identifiers, boundary conversion, and the resolution of context-dependent units.<br /> <br /> A single canonical representation:<br /> <br /> * provides an unambiguous data contract between AOWIS components;<br /> * prevents backend- or locale-specific units from leaking into the domain model;<br /> * simplifies validation, comparison, computation, serialization, and testing;<br /> * allows user interfaces and external systems to use alternative units without changing the authoritative representation.<br /> <br /> The canonical measurement quantities and units themselves are defined in [[Measurement:Canonical_Units]].<br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; Measurement quantity<br /> : A defined physical or engineering quantity being represented, such as volumetric flow rate, pressure head, power, or efficiency.<br /> <br /> ; Canonical unit<br /> : The single unit assigned by AOWIS to a measurement quantity for authoritative representation.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : A numerical value and unit received from a user, device, file, backend, component, or external system before conversion into the canonical AOWIS representation.<br /> <br /> ; Unit identifier<br /> : The machine-readable identifier of a unit. AOWIS uses UCUM for physical unit identifiers.<br /> <br /> ; Fixed-schema measurement field<br /> : A field whose measurement quantity and canonical unit are defined by the schema.<br /> <br /> ; Context-dependent measurement value<br /> : A value whose measurement quantity depends on another field, enum, object type, equation, or operating mode.<br /> <br /> == Requirements ==<br /> <br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing measurement quantities within the AOWIS domain model MUST be represented using the canonical unit defined for the measurement quantity.<br /> <br /> REQ-MEAS-002: Each fixed or resolved measurement quantity MUST be assigned exactly one canonical unit.<br /> <br /> REQ-MEAS-003: Measurement quantities with different meanings MUST remain distinct even when they use the same canonical unit.<br /> <br /> REQ-MEAS-004: Physical unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-005: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> <br /> REQ-MEAS-006: Dimensionless physical measurement quantities MUST use the UCUM unit identifier &quot;1&quot;. A fixed-schema field with canonical unit &quot;1&quot; MAY omit a unit suffix when its field name unambiguously identifies the quantity.<br /> <br /> REQ-MEAS-007: Numeric values that are not measurement quantities MUST NOT be assigned measurement units solely because they are numeric.<br /> <br /> REQ-MEAS-008: A value whose measurement quantity depends on another field, enum, object type, equation, or operating mode MUST be represented using quantity-specific fields or a discriminated structure that identifies the resolved quantity.<br /> <br /> REQ-MEAS-009: An equation coefficient whose dimensions depend on configurable equation parameters MUST retain the parameters required to determine its dimensional meaning and MUST NOT be represented using a misleading fixed unit.<br /> <br /> REQ-MEAS-010: Values entering the AOWIS domain model in non-canonical units MUST be converted to their defined canonical units at the applicable system boundary. Values leaving AOWIS MAY be converted to the representation required by the receiving system or interface.<br /> <br /> REQ-MEAS-011: Conversion artifacts, rounding errors, and precision loss introduced by an implementation MUST NOT exceed the documented precision of the measurement.<br /> <br /> REQ-MEAS-012: A retained non-canonical source representation MUST be clearly distinguished from the authoritative canonical value.<br /> <br /> REQ-MEAS-013: Monetary values that depend on a currency MUST identify that currency using its ISO 4217 alphabetic code or by reference to a configured currency carrying that code.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UI-001: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a measurement quantity.<br /> <br /> REQ-MEAS-UI-002: User interfaces MAY display measurement values in supported non-canonical units.<br /> <br /> REQ-MEAS-UI-003: User interfaces accepting values in non-canonical units MUST convert the entered value to its canonical unit before it enters the AOWIS domain model.<br /> <br /> REQ-MEAS-UI-004: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Interpretation of the Requirements ==<br /> <br /> ''This section is informative. The normative requirements above remain authoritative.''<br /> <br /> A canonical unit belongs to a '''measurement quantity''', not merely to a numeric data type. Two quantities can therefore use the same unit while remaining semantically different. For example, elevation, hydraulic head, pressure head, and water level are all expressed in metres but represent different quantities.<br /> <br /> Dimensionless physical quantities remain measurement quantities. Examples include demand multipliers, pump speed ratios, hydraulic coefficients, and exponents. Their canonical UCUM unit is &lt;code&gt;1&lt;/code&gt;. Fixed-schema fields normally express their meaning through the field name and do not need an artificial unit suffix such as &lt;code&gt;_1&lt;/code&gt;.<br /> <br /> Conversely, a number is not automatically a measurement. Counts, indices, priorities, identifiers, decimal precision settings, and similar values do not require measurement units.<br /> <br /> Some values cannot be assigned a unit until their context is known. A valve setting, for example, may represent pressure head, volumetric flow rate, valve position, a loss coefficient, or another quantity depending on the valve type. Such values must therefore be represented so that their actual measurement quantity is unambiguous.<br /> <br /> The same principle applies to control values, rule values, water-quality values, report thresholds, generic curve coordinates, and similar context-dependent data.<br /> <br /> Equation coefficients require additional care when their dimensional meaning depends on configurable equation parameters. For example, in an emitter relation<br /> <br /> &lt;pre&gt;<br /> Q = C H^n<br /> &lt;/pre&gt;<br /> <br /> the dimensional meaning of &lt;code&gt;C&lt;/code&gt; depends on the exponent &lt;code&gt;n&lt;/code&gt;. The coefficient and the parameters required to interpret it must therefore remain associated.<br /> <br /> Alternative backend, import, export, user-selected, and display units do not change the canonical AOWIS representation. Conversion occurs at the boundary where the alternative representation enters or leaves AOWIS.<br /> <br /> === Examples ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Value !! Interpretation<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate = 12.5 m3/h&lt;/code&gt; || Measurement quantity with canonical unit &lt;code&gt;m3/h&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;demand_multiplier = 1.2&lt;/code&gt; || Dimensionless measurement quantity with canonical UCUM unit &lt;code&gt;1&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;rule_priority = 5&lt;/code&gt; || Numeric value that is not a measurement quantity<br /> |-<br /> | FCV setting &lt;code&gt;20 m3/h&lt;/code&gt; || Setting resolved to volumetric flow rate<br /> |-<br /> | PRV setting &lt;code&gt;30 m&lt;/code&gt; || Setting resolved to pressure head<br /> |}<br /> <br /> == Boundary Conversion ==<br /> <br /> The AOWIS domain model uses canonical units independently of the unit systems used by backends, files, external systems, devices, or user interfaces.<br /> <br /> An adapter or interface is responsible for converting values whenever its representation differs from the canonical AOWIS representation.<br /> <br /> For example, an EPANET project MAY use any EPANET-supported flow or pressure unit system. The EPANET adapter converts those values to and from the canonical quantities defined in [[Measurement:Canonical_Units]].<br /> <br /> A backend configuration option that selects a backend unit system does not alter the canonical AOWIS data contract.<br /> <br /> == Fixed and Dynamic Schema Values ==<br /> <br /> For a fixed-schema field, the measurement quantity and canonical unit MAY be defined entirely by the schema.<br /> <br /> For example:<br /> <br /> &lt;pre&gt;<br /> flow_m3_per_h<br /> pressure_head_m<br /> power_kw<br /> &lt;/pre&gt;<br /> <br /> do not require a separate unit property when their schema definition unambiguously establishes the measurement quantity and unit.<br /> <br /> Generic or dynamically typed measurement values MUST identify or resolve to their measurement quantity. Where the unit is represented explicitly, the canonical UCUM identifier defined in [[Measurement:Canonical_Units]] MUST be used.<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the Model MUST follow this specification and the canonical quantity registry in [[Measurement:Canonical_Units]].<br /> <br /> == References ==<br /> <br /> &lt;references /&gt;<br /> <br /> * Unified Code for Units of Measure (UCUM)&lt;ref name=&quot;UCUM&quot;&gt;https://ucum.org&lt;/ref&gt;<br /> * International Bureau of Weights and Measures (BIPM), International System of Units (SI)&lt;ref name=&quot;BIPM&quot;&gt;https://www.bipm.org/en/measurement-units&lt;/ref&gt;<br /> * ISO 4217 currency codes&lt;ref name=&quot;ISO4217&quot;&gt;https://www.iso.org/iso-4217-currency-codes.html&lt;/ref&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=682 2026-08-18T17:19:14Z

<p>Samuel: </p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> This page is the normative registry of canonical measurement quantities and units used by AOWIS.<br /> <br /> The representation and conversion rules governing these quantities are defined in [[Measurement:Units]].<br /> <br /> UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is used for machine-readable physical unit identifiers.<br /> <br /> == Identifier and Field-Naming Rules ==<br /> <br /> The canonical unit assigned to each measurement quantity in this registry is authoritative.<br /> <br /> When a unit identifier is explicitly represented, it MUST use the canonical UCUM identifier defined here.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe naming convention used for fixed-schema field names, property names, database columns, and similar technical identifiers.<br /> <br /> The suffix convention is:<br /> <br /> * division is represented by &lt;code&gt;_per_&lt;/code&gt;;<br /> * multiplication is represented by &lt;code&gt;_&lt;/code&gt;;<br /> * unit symbols are normalized to lower case where required for identifier naming;<br /> * quantity-specific semantic qualifiers MAY be included where a literal unit-only suffix would be ambiguous;<br /> * dimensionless fields with canonical UCUM unit &lt;code&gt;1&lt;/code&gt; normally omit a unit suffix.<br /> <br /> For example:<br /> <br /> &lt;pre&gt;<br /> m3/h -&gt; m3_per_h<br /> m/s -&gt; m_per_s<br /> kW.h/m3 -&gt; kw_h_per_m3<br /> mm2/(100.m) -&gt; mm2_per_100m<br /> &lt;/pre&gt;<br /> <br /> The AOWIS identifier suffix is not itself a UCUM unit identifier.<br /> <br /> Generic or dynamically typed measurement values MUST identify their resolved measurement quantity and use the canonical unit defined by this registry.<br /> <br /> == Length and Distance Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |-<br /> | &lt;code&gt;darcy_weisbach_roughness_height&lt;/code&gt; || Absolute pipe-wall roughness height used by the Darcy-Weisbach formulation || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET Darcy-Weisbach pipe roughness<br /> |}<br /> <br /> == Geographic Coordinate Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Projected-coordinate easting<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Projected-coordinate northing<br /> |-<br /> | &lt;code&gt;local_x&lt;/code&gt; || X coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local coordinates when the coordinate system is defined in metres<br /> |-<br /> | &lt;code&gt;local_y&lt;/code&gt; || Y coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local coordinates when the coordinate system is defined in metres<br /> |}<br /> <br /> == Area and Volume Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> == Flow and Transport Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> == Hydraulic Head, Pressure, and Stress Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis<br /> |}<br /> <br /> == Time Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration and time steps<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time and clock-time controls<br /> |}<br /> <br /> == Hydraulic Coefficients and Other Dimensionless Quantities ==<br /> <br /> The canonical UCUM unit identifier for all quantities in this section is &lt;code&gt;1&lt;/code&gt;. The AOWIS unit suffix is omitted.<br /> <br /> Semantic terms such as &lt;code&gt;ratio&lt;/code&gt;, &lt;code&gt;factor&lt;/code&gt;, &lt;code&gt;coefficient&lt;/code&gt;, &lt;code&gt;multiplier&lt;/code&gt;, and &lt;code&gt;exponent&lt;/code&gt; describe the quantity and are not unit suffixes.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hazen_williams_roughness_coefficient&lt;/code&gt; || Hazen-Williams pipe roughness coefficient || &lt;code&gt;1&lt;/code&gt; || none || EPANET Hazen-Williams roughness<br /> |-<br /> | &lt;code&gt;chezy_manning_roughness_coefficient&lt;/code&gt; || Chezy-Manning pipe roughness coefficient || &lt;code&gt;1&lt;/code&gt; || none || EPANET Chezy-Manning roughness<br /> |-<br /> | &lt;code&gt;minor_loss_coefficient&lt;/code&gt; || Coefficient representing local hydraulic losses || &lt;code&gt;1&lt;/code&gt; || none || Pipe and valve minor loss; TCV setting<br /> |-<br /> | &lt;code&gt;darcy_weisbach_friction_factor&lt;/code&gt; || Darcy-Weisbach friction factor || &lt;code&gt;1&lt;/code&gt; || none || Pipe simulation result<br /> |-<br /> | &lt;code&gt;pump_speed_ratio&lt;/code&gt; || Pump rotational speed relative to nominal or reference speed || &lt;code&gt;1&lt;/code&gt; || none || Pump setting, result, pattern, control, and rule values<br /> |-<br /> | &lt;code&gt;pattern_multiplier&lt;/code&gt; || Factor applied by a hydraulic or energy pattern || &lt;code&gt;1&lt;/code&gt; || none || EPANET pattern factor<br /> |-<br /> | &lt;code&gt;demand_multiplier&lt;/code&gt; || Global factor applied to base demands || &lt;code&gt;1&lt;/code&gt; || none || EPANET demand multiplier<br /> |-<br /> | &lt;code&gt;pressure_exponent&lt;/code&gt; || Exponent used by the pressure-driven demand relation || &lt;code&gt;1&lt;/code&gt; || none || EPANET pressure exponent<br /> |-<br /> | &lt;code&gt;emitter_exponent&lt;/code&gt; || Exponent used by the emitter pressure-flow relation || &lt;code&gt;1&lt;/code&gt; || none || EPANET emitter exponent<br /> |-<br /> | &lt;code&gt;reaction_order&lt;/code&gt; || Order of a bulk, wall, or tank reaction equation || &lt;code&gt;1&lt;/code&gt; || none || EPANET reaction order<br /> |-<br /> | &lt;code&gt;specific_gravity&lt;/code&gt; || Fluid density relative to a defined reference density || &lt;code&gt;1&lt;/code&gt; || none || EPANET specific gravity<br /> |-<br /> | &lt;code&gt;relative_viscosity&lt;/code&gt; || Kinematic viscosity relative to the solver reference || &lt;code&gt;1&lt;/code&gt; || none || EPANET relative viscosity<br /> |-<br /> | &lt;code&gt;relative_diffusivity&lt;/code&gt; || Molecular diffusivity relative to the solver reference || &lt;code&gt;1&lt;/code&gt; || none || EPANET relative diffusivity<br /> |-<br /> | &lt;code&gt;mixing_fraction&lt;/code&gt; || Fraction of tank volume assigned to the applicable mixing zone || &lt;code&gt;1&lt;/code&gt; || none || EPANET tank mixing fraction<br /> |-<br /> | &lt;code&gt;hydraulic_accuracy&lt;/code&gt; || Relative hydraulic convergence criterion || &lt;code&gt;1&lt;/code&gt; || none || EPANET hydraulic accuracy<br /> |-<br /> | &lt;code&gt;hydraulic_damping_limit&lt;/code&gt; || Relative threshold controlling solver damping or status checks || &lt;code&gt;1&lt;/code&gt; || none || EPANET damping limit<br /> |-<br /> | &lt;code&gt;relative_error&lt;/code&gt; || Relative numerical error || &lt;code&gt;1&lt;/code&gt; || none || Hydraulic simulation statistics<br /> |-<br /> | &lt;code&gt;flow_balance_ratio&lt;/code&gt; || Ratio of total outflow to total inflow || &lt;code&gt;1&lt;/code&gt; || none || EPANET flow-balance reporting<br /> |-<br /> | &lt;code&gt;quality_mass_balance_ratio&lt;/code&gt; || Water-quality mass-conservation ratio || &lt;code&gt;1&lt;/code&gt; || none || EPANET quality mass-balance reporting<br /> |}<br /> <br /> == Percentage Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |-<br /> | &lt;code&gt;operating_time_percentage&lt;/code&gt; || Fraction of a reporting period during which equipment operates || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump energy reporting<br /> |-<br /> | &lt;code&gt;demand_reduction_percentage&lt;/code&gt; || Reduction in delivered demand relative to requested demand || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Hydraulic statistics<br /> |-<br /> | &lt;code&gt;leakage_loss_percentage&lt;/code&gt; || Leakage loss relative to total system inflow || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Leakage statistics<br /> |}<br /> <br /> == Reaction and Leakage Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe, and tank first-order bulk reactions<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe first-order wall reactions<br /> |-<br /> | &lt;code&gt;leak_area_per_100m_pipe_length&lt;/code&gt; || Effective leak area assigned per 100 metres of pipe length || square millimetre per 100 metres (mm²/100 m) || &lt;code&gt;mm2/(100.m)&lt;/code&gt; || &lt;code&gt;mm2_per_100m&lt;/code&gt; || EPANET 2.3 FAVAD leak area; EPANET uses 100 project length units and the adapter converts when required&lt;ref name=&quot;EPANET23&quot;&gt;OWA-EPANET 2.3 release notes https://github.com/OpenWaterAnalytics/EPANET/blob/v2.3/ReleaseNotes2_3.md&lt;/ref&gt;<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre of pressure head (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m_head&lt;/code&gt; || EPANET 2.3 FAVAD leak expansion<br /> |}<br /> <br /> == Water Quality Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || Chemical quality input and results<br /> |-<br /> | &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt; || Chemical mass introduced into or transported through the system per unit time || milligram per minute (mg/min) || &lt;code&gt;mg/min&lt;/code&gt; || &lt;code&gt;mg_per_min&lt;/code&gt; || EPANET mass-booster source strength and source mass rate<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> == Power, Energy, and Electrical Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == References ==<br /> <br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=681 2026-08-18T17:18:50Z

<p>Samuel: </p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Canonical_Units]]<br /> <br /> AOWIS uses a canonical representation for measurement quantities. Each measurement quantity has one canonical unit defined in [[Measurement:Canonical_Units|Canonical Units]].<br /> <br /> Canonical units are selected individually based on SI, established engineering practice, numerical practicality, and interoperability. Values MAY use other units at system boundaries and in user interfaces, but the authoritative AOWIS representation remains canonical.<br /> <br /> == Purpose ==<br /> <br /> This specification defines how measurement quantities, values, units, conversions, and measurement-related numeric data are represented and handled by AOWIS.<br /> <br /> A single canonical representation:<br /> <br /> * provides an unambiguous data contract between AOWIS components;<br /> * prevents backend- or locale-specific units from leaking into the domain model;<br /> * simplifies validation, comparison, computation, serialization, and testing;<br /> * allows user interfaces and external systems to use alternative units without changing the authoritative representation.<br /> <br /> The canonical measurement quantities and units themselves are defined in [[Measurement:Canonical_Units]].<br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; Measurement quantity<br /> : A defined physical or engineering quantity being represented, such as volumetric flow rate, pressure head, power, or efficiency.<br /> <br /> ; Canonical unit<br /> : The single unit assigned by AOWIS to a measurement quantity for authoritative representation.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : A numerical value and unit received from a user, device, file, backend, component, or external system before conversion into the canonical AOWIS representation.<br /> <br /> ; Unit identifier<br /> : The machine-readable identifier of a unit. AOWIS uses UCUM for physical unit identifiers.<br /> <br /> ; Fixed-schema measurement field<br /> : A field whose measurement quantity and canonical unit are defined by the schema.<br /> <br /> ; Context-dependent measurement value<br /> : A value whose measurement quantity depends on another field, enum, object type, equation, or operating mode.<br /> <br /> == Requirements ==<br /> <br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing measurement quantities within the AOWIS domain model MUST be represented using the canonical unit defined for the measurement quantity.<br /> <br /> REQ-MEAS-002: Each fixed or resolved measurement quantity MUST be assigned exactly one canonical unit.<br /> <br /> REQ-MEAS-003: Measurement quantities with different meanings MUST remain distinct even when they use the same canonical unit.<br /> <br /> REQ-MEAS-004: Physical unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-005: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> <br /> REQ-MEAS-006: Dimensionless physical measurement quantities MUST use the UCUM unit identifier &quot;1&quot;. A fixed-schema field with canonical unit &quot;1&quot; MAY omit a unit suffix when its field name unambiguously identifies the quantity.<br /> <br /> REQ-MEAS-007: Numeric values that are not measurement quantities MUST NOT be assigned measurement units solely because they are numeric.<br /> <br /> REQ-MEAS-008: A value whose measurement quantity depends on another field, enum, object type, equation, or operating mode MUST be represented using quantity-specific fields or a discriminated structure that identifies the resolved quantity.<br /> <br /> REQ-MEAS-009: An equation coefficient whose dimensions depend on configurable equation parameters MUST retain the parameters required to determine its dimensional meaning and MUST NOT be represented using a misleading fixed unit.<br /> <br /> REQ-MEAS-010: Values entering the AOWIS domain model in non-canonical units MUST be converted to their defined canonical units at the applicable system boundary. Values leaving AOWIS MAY be converted to the representation required by the receiving system or interface.<br /> <br /> REQ-MEAS-011: Conversion artifacts, rounding errors, and precision loss introduced by an implementation MUST NOT exceed the documented precision of the measurement.<br /> <br /> REQ-MEAS-012: Original source values and unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-013: Monetary values that depend on a currency MUST identify that currency using its ISO 4217 alphabetic code or by reference to a configured currency carrying that code.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UI-001: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a measurement quantity.<br /> <br /> REQ-MEAS-UI-002: User interfaces MAY display measurement values in supported non-canonical units.<br /> <br /> REQ-MEAS-UI-003: User interfaces accepting values in non-canonical units MUST convert the entered value to its canonical unit before it enters the AOWIS domain model.<br /> <br /> REQ-MEAS-UI-004: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Interpretation of the Requirements ==<br /> <br /> ''This section is informative. The normative requirements above remain authoritative.''<br /> <br /> A canonical unit belongs to a '''measurement quantity''', not merely to a numeric data type. Two quantities can therefore use the same unit while remaining semantically different. For example, elevation, hydraulic head, pressure head, and water level are all expressed in metres but represent different quantities.<br /> <br /> Dimensionless physical quantities remain measurement quantities. Examples include demand multipliers, pump speed ratios, hydraulic coefficients, and exponents. Their canonical UCUM unit is &lt;code&gt;1&lt;/code&gt;. Fixed-schema fields normally express their meaning through the field name and do not need an artificial unit suffix such as &lt;code&gt;_1&lt;/code&gt;.<br /> <br /> Conversely, a number is not automatically a measurement. Counts, indices, priorities, identifiers, decimal precision settings, and similar values do not require measurement units.<br /> <br /> Some values cannot be assigned a unit until their context is known. A valve setting, for example, may represent pressure head, volumetric flow rate, valve position, a loss coefficient, or another quantity depending on the valve type. Such values must therefore be represented so that their actual measurement quantity is unambiguous.<br /> <br /> The same principle applies to control values, rule values, water-quality values, report thresholds, generic curve coordinates, and similar context-dependent data.<br /> <br /> Equation coefficients require additional care when their dimensional meaning depends on configurable equation parameters. For example, in an emitter relation<br /> <br /> &lt;pre&gt;<br /> Q = C H^n<br /> &lt;/pre&gt;<br /> <br /> the dimensional meaning of &lt;code&gt;C&lt;/code&gt; depends on the exponent &lt;code&gt;n&lt;/code&gt;. The coefficient and the parameters required to interpret it must therefore remain associated.<br /> <br /> Alternative backend, import, export, user-selected, and display units do not change the canonical AOWIS representation. Conversion occurs at the boundary where the alternative representation enters or leaves AOWIS.<br /> <br /> === Examples ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Value !! Interpretation<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate = 12.5 m3/h&lt;/code&gt; || Measurement quantity with canonical unit &lt;code&gt;m3/h&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;demand_multiplier = 1.2&lt;/code&gt; || Dimensionless measurement quantity with canonical UCUM unit &lt;code&gt;1&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;rule_priority = 5&lt;/code&gt; || Numeric value that is not a measurement quantity<br /> |-<br /> | FCV setting &lt;code&gt;20 m3/h&lt;/code&gt; || Setting resolved to volumetric flow rate<br /> |-<br /> | PRV setting &lt;code&gt;30 m&lt;/code&gt; || Setting resolved to pressure head<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> The following concepts cannot be assigned one fixed canonical unit until their applicable context has been resolved.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Model Concept !! Context-Dependent Meaning !! Required Representation<br /> |-<br /> | Valve setting || PRV, PSV, and PBV: pressure head; FCV: volumetric flow rate; TCV: minor-loss coefficient; PCV: valve position; GPV: curve reference || Use quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Pump setting || Pump speed relative to nominal speed || Resolve as &lt;code&gt;pump_speed_ratio&lt;/code&gt;<br /> |-<br /> | Control action setting || Quantity supported by the controlled link type || Use the same quantity-specific setting representation as the target link<br /> |-<br /> | Control trigger || Water level, pressure head, elapsed time, or time of day depending on control type || Use quantity-specific trigger representations<br /> |-<br /> | Rule premise value || Quantity selected by the rule variable || Store or resolve the rule variable together with its quantity-specific value<br /> |-<br /> | Rule action setting || Quantity supported by the target link || Use the target link's quantity-specific setting representation<br /> |-<br /> | Initial and simulated quality || Chemical concentration, water age, or source-trace percentage depending on analysis mode || Resolve through the active quality-analysis mode<br /> |-<br /> | Water-quality solver tolerance || Quantity depends on quality-analysis mode || Resolve through the active quality-analysis mode<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate depending on source type || Use a source-type-specific representation<br /> |-<br /> | Reaction coefficient || Dimensions depend on reaction order || Use fixed quantities only for defined fixed-order cases; otherwise retain the reaction order with the coefficient<br /> |-<br /> | Emitter coefficient || In &lt;code&gt;Q = C H^n&lt;/code&gt;, the dimensional meaning of &lt;code&gt;C&lt;/code&gt; depends on &lt;code&gt;n&lt;/code&gt; || Store coefficient and exponent together<br /> |-<br /> | Generic curve coordinates || Quantities depend on curve type || Prefer typed curve structures; genuinely generic curves require explicit quantity metadata<br /> |-<br /> | Report thresholds || Quantity depends on the corresponding report field || Associate each threshold with the report field's measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate interpretation depends on the associated map configuration || Resolve to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Boundary Conversion ==<br /> <br /> The AOWIS domain model uses canonical units independently of the unit systems used by backends, files, external systems, devices, or user interfaces.<br /> <br /> An adapter or interface is responsible for converting values whenever its representation differs from the canonical AOWIS representation.<br /> <br /> For example, an EPANET project MAY use any EPANET-supported flow or pressure unit system. The EPANET adapter converts those values to and from the canonical quantities defined in [[Measurement:Canonical_Units]].<br /> <br /> A backend configuration option that selects a backend unit system does not alter the canonical AOWIS data contract.<br /> <br /> == Fixed and Dynamic Schema Values ==<br /> <br /> For a fixed-schema field, the measurement quantity and canonical unit MAY be defined entirely by the schema.<br /> <br /> For example:<br /> <br /> &lt;pre&gt;<br /> flow_m3_per_h<br /> pressure_head_m<br /> power_kw<br /> &lt;/pre&gt;<br /> <br /> do not require a separate unit property when their schema definition unambiguously establishes the measurement quantity and unit.<br /> <br /> Generic or dynamically typed measurement values MUST identify or resolve to their measurement quantity. Where the unit is represented explicitly, the canonical UCUM identifier defined in [[Measurement:Canonical_Units]] MUST be used.<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the Model MUST follow this specification and the canonical quantity registry in [[Measurement:Canonical_Units]].<br /> <br /> == References ==<br /> <br /> &lt;references /&gt;<br /> <br /> * Unified Code for Units of Measure (UCUM)&lt;ref name=&quot;UCUM&quot;&gt;https://ucum.org&lt;/ref&gt;<br /> * International Bureau of Weights and Measures (BIPM), International System of Units (SI)&lt;ref name=&quot;BIPM&quot;&gt;https://www.bipm.org/en/measurement-units&lt;/ref&gt;<br /> * ISO 4217 currency codes&lt;ref name=&quot;ISO4217&quot;&gt;https://www.iso.org/iso-4217-currency-codes.html&lt;/ref&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Main_Page&diff=680 2026-08-18T17:18:08Z

<p>Samuel: </p> <hr /> <div><br /> Measurements are fundamental to AOWIS operations. Decisions in monitoring, control, maintenance, planning, safety, and research depend on reliable measurement data.<br /> <br /> This Domain defines how AOWIS represents, records, exchanges, validates, and interprets measurements across water, agricultural, environmental, and infrastructure systems.<br /> <br /> == Core Specifications ==<br /> <br /> * [[Measurement:Units|Units]]<br /> * [[Measurement:Canonical_Units|Canonical Units]]<br /> <br /> == Subsystems ==<br /> <br /> * [[Measurement:Elevation|Elevation]]<br /> * [[Measurement:Time]]<br /> * [[Measurement:Quality]]<br /> * [[Measurement:Calibration]]<br /> <br /> == Supporting Concepts ==<br /> <br /> * Measurement sources<br /> * Data validation<br /> * Uncertainty handling<br /> * Storage &amp; exchange rules<br /> <br /> == Hardware ==<br /> <br /> * [[Measurement:Pressure_Sensor_Examples|Pressure sensor examples]]</div>

Samuel https://aowis.org/index.php?title=Measurement:Main_Page&diff=679 2026-08-18T17:17:25Z

<p>Samuel: </p> <hr /> <div>= Measurement =<br /> <br /> Measurements are fundamental to AOWIS operations. Decisions in monitoring, control, maintenance, planning, safety, and research depend on reliable measurement data.<br /> <br /> This Domain defines how AOWIS represents, records, exchanges, validates, and interprets measurements across water, agricultural, environmental, and infrastructure systems.<br /> <br /> == Core Specifications ==<br /> <br /> * [[Measurement:Units|Units]]<br /> * [[Measurement:Canonical_Units|Canonical Units]]<br /> <br /> == Subsystems ==<br /> <br /> * [[Measurement:Elevation|Elevation]]<br /> * [[Measurement:Time]]<br /> * [[Measurement:Quality]]<br /> * [[Measurement:Calibration]]<br /> <br /> == Supporting Concepts ==<br /> <br /> * Measurement sources<br /> * Data validation<br /> * Uncertainty handling<br /> * Storage &amp; exchange rules<br /> <br /> == Hardware ==<br /> <br /> * [[Measurement:Pressure_Sensor_Examples|Pressure sensor examples]]</div>

Samuel https://aowis.org/index.php?title=Measurement:Main_Page&diff=678 2026-08-18T16:05:37Z

<p>Samuel: </p> <hr /> <div>= Measurement =<br /> <br /> Measurements are fundamental to AOWIS operations. Decisions in monitoring, control, maintenance, planning, safety, and research depend on reliable measurement data.<br /> <br /> This Domain defines how AOWIS represents, records, exchanges, validates, and interprets measurements across water, agricultural, environmental, and infrastructure systems.<br /> <br /> == Core Specifications ==<br /> <br /> * [[Measurement:Units|Unit System Requirements (SI)]]<br /> * [[Measurement:Canonical_Units|Canonical Units]]<br /> <br /> == Subsystems ==<br /> <br /> * [[Measurement:Elevation|Elevation]]<br /> * [[Measurement:Time]]<br /> * [[Measurement:Quality]]<br /> * [[Measurement:Calibration]]<br /> <br /> == Supporting Concepts ==<br /> <br /> * Measurement sources<br /> * Data validation<br /> * Uncertainty handling<br /> * Storage &amp; exchange rules<br /> <br /> == Hardware ==<br /> * [[Measurement:Pressure Sensor Examples|Pressure sensor examples]]</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=677 2026-08-18T15:22:48Z

<p>Samuel: Samuel moved page Measurement:Unit Identifiers to Measurement:Canonical Units without leaving a redirect</p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> This page is the normative registry of canonical measurement quantities and units used by AOWIS.<br /> <br /> The representation and conversion rules governing these quantities are defined in [[Measurement:Units]].<br /> <br /> UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is used for machine-readable physical unit identifiers.<br /> <br /> == Identifier and Field-Naming Rules ==<br /> <br /> The canonical unit assigned to each measurement quantity in this registry is authoritative.<br /> <br /> When a unit identifier is explicitly represented, it MUST use the canonical UCUM identifier defined here.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe naming convention used for fixed-schema field names, property names, database columns, and similar technical identifiers.<br /> <br /> The suffix convention is:<br /> <br /> * division is represented by &lt;code&gt;_per_&lt;/code&gt;;<br /> * multiplication is represented by &lt;code&gt;_&lt;/code&gt;;<br /> * unit symbols are normalized to lower case where required for identifier naming;<br /> * quantity-specific semantic qualifiers MAY be included where a literal unit-only suffix would be ambiguous;<br /> * dimensionless fields with canonical UCUM unit &lt;code&gt;1&lt;/code&gt; normally omit a unit suffix.<br /> <br /> For example:<br /> <br /> &lt;pre&gt;<br /> m3/h -&gt; m3_per_h<br /> m/s -&gt; m_per_s<br /> kW.h/m3 -&gt; kw_h_per_m3<br /> mm2/(100.m) -&gt; mm2_per_100m<br /> &lt;/pre&gt;<br /> <br /> The AOWIS identifier suffix is not itself a UCUM unit identifier.<br /> <br /> Generic or dynamically typed measurement values MUST identify their resolved measurement quantity and use the canonical unit defined by this registry.<br /> <br /> == Length and Distance Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |-<br /> | &lt;code&gt;darcy_weisbach_roughness_height&lt;/code&gt; || Absolute pipe-wall roughness height used by the Darcy-Weisbach formulation || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET Darcy-Weisbach pipe roughness<br /> |}<br /> <br /> == Geographic Coordinate Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Projected-coordinate easting<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Projected-coordinate northing<br /> |-<br /> | &lt;code&gt;local_x&lt;/code&gt; || X coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local coordinates when the coordinate system is defined in metres<br /> |-<br /> | &lt;code&gt;local_y&lt;/code&gt; || Y coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local coordinates when the coordinate system is defined in metres<br /> |}<br /> <br /> == Area and Volume Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> == Flow and Transport Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> == Hydraulic Head, Pressure, and Stress Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis<br /> |}<br /> <br /> == Time Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration and time steps<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time and clock-time controls<br /> |}<br /> <br /> == Hydraulic Coefficients and Other Dimensionless Quantities ==<br /> <br /> The canonical UCUM unit identifier for all quantities in this section is &lt;code&gt;1&lt;/code&gt;. The AOWIS unit suffix is omitted.<br /> <br /> Semantic terms such as &lt;code&gt;ratio&lt;/code&gt;, &lt;code&gt;factor&lt;/code&gt;, &lt;code&gt;coefficient&lt;/code&gt;, &lt;code&gt;multiplier&lt;/code&gt;, and &lt;code&gt;exponent&lt;/code&gt; describe the quantity and are not unit suffixes.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hazen_williams_roughness_coefficient&lt;/code&gt; || Hazen-Williams pipe roughness coefficient || &lt;code&gt;1&lt;/code&gt; || none || EPANET Hazen-Williams roughness<br /> |-<br /> | &lt;code&gt;chezy_manning_roughness_coefficient&lt;/code&gt; || Chezy-Manning pipe roughness coefficient || &lt;code&gt;1&lt;/code&gt; || none || EPANET Chezy-Manning roughness<br /> |-<br /> | &lt;code&gt;minor_loss_coefficient&lt;/code&gt; || Coefficient representing local hydraulic losses || &lt;code&gt;1&lt;/code&gt; || none || Pipe and valve minor loss; TCV setting<br /> |-<br /> | &lt;code&gt;darcy_weisbach_friction_factor&lt;/code&gt; || Darcy-Weisbach friction factor || &lt;code&gt;1&lt;/code&gt; || none || Pipe simulation result<br /> |-<br /> | &lt;code&gt;pump_speed_ratio&lt;/code&gt; || Pump rotational speed relative to nominal or reference speed || &lt;code&gt;1&lt;/code&gt; || none || Pump setting, result, pattern, control, and rule values<br /> |-<br /> | &lt;code&gt;pattern_multiplier&lt;/code&gt; || Factor applied by a hydraulic or energy pattern || &lt;code&gt;1&lt;/code&gt; || none || EPANET pattern factor<br /> |-<br /> | &lt;code&gt;demand_multiplier&lt;/code&gt; || Global factor applied to base demands || &lt;code&gt;1&lt;/code&gt; || none || EPANET demand multiplier<br /> |-<br /> | &lt;code&gt;pressure_exponent&lt;/code&gt; || Exponent used by the pressure-driven demand relation || &lt;code&gt;1&lt;/code&gt; || none || EPANET pressure exponent<br /> |-<br /> | &lt;code&gt;emitter_exponent&lt;/code&gt; || Exponent used by the emitter pressure-flow relation || &lt;code&gt;1&lt;/code&gt; || none || EPANET emitter exponent<br /> |-<br /> | &lt;code&gt;reaction_order&lt;/code&gt; || Order of a bulk, wall, or tank reaction equation || &lt;code&gt;1&lt;/code&gt; || none || EPANET reaction order<br /> |-<br /> | &lt;code&gt;specific_gravity&lt;/code&gt; || Fluid density relative to a defined reference density || &lt;code&gt;1&lt;/code&gt; || none || EPANET specific gravity<br /> |-<br /> | &lt;code&gt;relative_viscosity&lt;/code&gt; || Kinematic viscosity relative to the solver reference || &lt;code&gt;1&lt;/code&gt; || none || EPANET relative viscosity<br /> |-<br /> | &lt;code&gt;relative_diffusivity&lt;/code&gt; || Molecular diffusivity relative to the solver reference || &lt;code&gt;1&lt;/code&gt; || none || EPANET relative diffusivity<br /> |-<br /> | &lt;code&gt;mixing_fraction&lt;/code&gt; || Fraction of tank volume assigned to the applicable mixing zone || &lt;code&gt;1&lt;/code&gt; || none || EPANET tank mixing fraction<br /> |-<br /> | &lt;code&gt;hydraulic_accuracy&lt;/code&gt; || Relative hydraulic convergence criterion || &lt;code&gt;1&lt;/code&gt; || none || EPANET hydraulic accuracy<br /> |-<br /> | &lt;code&gt;hydraulic_damping_limit&lt;/code&gt; || Relative threshold controlling solver damping or status checks || &lt;code&gt;1&lt;/code&gt; || none || EPANET damping limit<br /> |-<br /> | &lt;code&gt;relative_error&lt;/code&gt; || Relative numerical error || &lt;code&gt;1&lt;/code&gt; || none || Hydraulic simulation statistics<br /> |-<br /> | &lt;code&gt;flow_balance_ratio&lt;/code&gt; || Ratio of total outflow to total inflow || &lt;code&gt;1&lt;/code&gt; || none || EPANET flow-balance reporting<br /> |-<br /> | &lt;code&gt;quality_mass_balance_ratio&lt;/code&gt; || Water-quality mass-conservation ratio || &lt;code&gt;1&lt;/code&gt; || none || EPANET quality mass-balance reporting<br /> |}<br /> <br /> == Percentage Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |-<br /> | &lt;code&gt;operating_time_percentage&lt;/code&gt; || Fraction of a reporting period during which equipment operates || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump energy reporting<br /> |-<br /> | &lt;code&gt;demand_reduction_percentage&lt;/code&gt; || Reduction in delivered demand relative to requested demand || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Hydraulic statistics<br /> |-<br /> | &lt;code&gt;leakage_loss_percentage&lt;/code&gt; || Leakage loss relative to total system inflow || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Leakage statistics<br /> |}<br /> <br /> == Reaction and Leakage Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe, and tank first-order bulk reactions<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe first-order wall reactions<br /> |-<br /> | &lt;code&gt;leak_area_per_100m_pipe_length&lt;/code&gt; || Effective leak area assigned per 100 metres of pipe length || square millimetre per 100 metres (mm²/100 m) || &lt;code&gt;mm2/(100.m)&lt;/code&gt; || &lt;code&gt;mm2_per_100m&lt;/code&gt; || EPANET 2.3 FAVAD leak area; EPANET uses 100 project length units and the adapter converts when required&lt;ref name=&quot;EPANET23&quot;&gt;OWA-EPANET 2.3 release notes https://github.com/OpenWaterAnalytics/EPANET/blob/v2.3/ReleaseNotes2_3.md&lt;/ref&gt;<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre of pressure head (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m_head&lt;/code&gt; || EPANET 2.3 FAVAD leak expansion<br /> |}<br /> <br /> == Water Quality Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || Chemical quality input and results<br /> |-<br /> | &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt; || Chemical mass introduced into or transported through the system per unit time || milligram per minute (mg/min) || &lt;code&gt;mg/min&lt;/code&gt; || &lt;code&gt;mg_per_min&lt;/code&gt; || EPANET mass-booster source strength and source mass rate<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> == Power, Energy, and Electrical Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> The following concepts cannot be assigned one fixed canonical unit until their applicable context has been resolved.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Model Concept !! Context-Dependent Meaning !! Required Representation<br /> |-<br /> | Valve setting || PRV, PSV, and PBV: pressure head; FCV: volumetric flow rate; TCV: minor-loss coefficient; PCV: valve position; GPV: curve reference || Use quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Pump setting || Pump speed relative to nominal speed || Resolve as &lt;code&gt;pump_speed_ratio&lt;/code&gt;<br /> |-<br /> | Control action setting || Quantity supported by the controlled link type || Use the same quantity-specific setting representation as the target link<br /> |-<br /> | Control trigger || Water level, pressure head, elapsed time, or time of day depending on control type || Use quantity-specific trigger representations<br /> |-<br /> | Rule premise value || Quantity selected by the rule variable || Store or resolve the rule variable together with its quantity-specific value<br /> |-<br /> | Rule action setting || Quantity supported by the target link || Use the target link's quantity-specific setting representation<br /> |-<br /> | Initial and simulated quality || Chemical concentration, water age, or source-trace percentage depending on analysis mode || Resolve through the active quality-analysis mode<br /> |-<br /> | Water-quality solver tolerance || Quantity depends on quality-analysis mode || Resolve through the active quality-analysis mode<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate depending on source type || Use a source-type-specific representation<br /> |-<br /> | Reaction coefficient || Dimensions depend on reaction order || Use fixed quantities only for defined fixed-order cases; otherwise retain the reaction order with the coefficient<br /> |-<br /> | Emitter coefficient || In &lt;code&gt;Q = C H^n&lt;/code&gt;, the dimensional meaning of &lt;code&gt;C&lt;/code&gt; depends on &lt;code&gt;n&lt;/code&gt; || Store coefficient and exponent together<br /> |-<br /> | Generic curve coordinates || Quantities depend on curve type || Prefer typed curve structures; genuinely generic curves require explicit quantity metadata<br /> |-<br /> | Report thresholds || Quantity depends on the corresponding report field || Associate each threshold with the report field's measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate interpretation depends on the associated map configuration || Resolve to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Monetary Values ==<br /> <br /> Monetary values that depend on a currency MUST identify that currency using its ISO 4217 alphabetic code or by reference to a configured currency carrying that code.&lt;ref name=&quot;ISO4217&quot;&gt;ISO 4217 currency codes https://www.iso.org/iso-4217-currency-codes.html&lt;/ref&gt;<br /> <br /> Where a monetary value is normalized by a physical quantity, the physical quantity uses the canonical unit defined by this registry.<br /> <br /> For example:<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Concept !! Physical Denominator<br /> |-<br /> | Energy price || kilowatt-hour (kWh)<br /> |-<br /> | Demand charge || kilowatt (kW)<br /> |-<br /> | Daily cost rate || day (d)<br /> |}<br /> <br /> == AOWIS Model and Backend Mapping ==<br /> <br /> Fixed-schema Model fields encode their canonical unit through the schema and, where applicable, the AOWIS identifier suffix.<br /> <br /> Backend-selected unit systems MUST NOT alter those field semantics.<br /> <br /> The EPANET adapter converts backend values whenever the EPANET project representation differs from the canonical AOWIS representation. Relevant mappings include:<br /> <br /> * volumetric flow rate → &lt;code&gt;m3/h&lt;/code&gt;;<br /> * length and hydraulic head → &lt;code&gt;m&lt;/code&gt;;<br /> * link diameter → &lt;code&gt;mm&lt;/code&gt;;<br /> * tank diameter → &lt;code&gt;m&lt;/code&gt;;<br /> * Darcy-Weisbach roughness → &lt;code&gt;mm&lt;/code&gt;;<br /> * head-loss gradient → &lt;code&gt;m/km&lt;/code&gt;;<br /> * leakage area → &lt;code&gt;mm2/(100.m)&lt;/code&gt;;<br /> * leakage expansion → &lt;code&gt;mm2/m&lt;/code&gt; of pressure head;<br /> * energy intensity → &lt;code&gt;kW.h/m3&lt;/code&gt;;<br /> * chemical concentration → &lt;code&gt;mg/L&lt;/code&gt;;<br /> * chemical mass flow rate → &lt;code&gt;mg/min&lt;/code&gt;.<br /> <br /> == References ==<br /> <br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=676 2026-08-18T15:20:42Z

<p>Samuel: </p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> This page is the normative registry of canonical measurement quantities and units used by AOWIS.<br /> <br /> The representation and conversion rules governing these quantities are defined in [[Measurement:Units]].<br /> <br /> UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is used for machine-readable physical unit identifiers.<br /> <br /> == Identifier and Field-Naming Rules ==<br /> <br /> The canonical unit assigned to each measurement quantity in this registry is authoritative.<br /> <br /> When a unit identifier is explicitly represented, it MUST use the canonical UCUM identifier defined here.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe naming convention used for fixed-schema field names, property names, database columns, and similar technical identifiers.<br /> <br /> The suffix convention is:<br /> <br /> * division is represented by &lt;code&gt;_per_&lt;/code&gt;;<br /> * multiplication is represented by &lt;code&gt;_&lt;/code&gt;;<br /> * unit symbols are normalized to lower case where required for identifier naming;<br /> * quantity-specific semantic qualifiers MAY be included where a literal unit-only suffix would be ambiguous;<br /> * dimensionless fields with canonical UCUM unit &lt;code&gt;1&lt;/code&gt; normally omit a unit suffix.<br /> <br /> For example:<br /> <br /> &lt;pre&gt;<br /> m3/h -&gt; m3_per_h<br /> m/s -&gt; m_per_s<br /> kW.h/m3 -&gt; kw_h_per_m3<br /> mm2/(100.m) -&gt; mm2_per_100m<br /> &lt;/pre&gt;<br /> <br /> The AOWIS identifier suffix is not itself a UCUM unit identifier.<br /> <br /> Generic or dynamically typed measurement values MUST identify their resolved measurement quantity and use the canonical unit defined by this registry.<br /> <br /> == Length and Distance Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |-<br /> | &lt;code&gt;darcy_weisbach_roughness_height&lt;/code&gt; || Absolute pipe-wall roughness height used by the Darcy-Weisbach formulation || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET Darcy-Weisbach pipe roughness<br /> |}<br /> <br /> == Geographic Coordinate Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Projected-coordinate easting<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Projected-coordinate northing<br /> |-<br /> | &lt;code&gt;local_x&lt;/code&gt; || X coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local coordinates when the coordinate system is defined in metres<br /> |-<br /> | &lt;code&gt;local_y&lt;/code&gt; || Y coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local coordinates when the coordinate system is defined in metres<br /> |}<br /> <br /> == Area and Volume Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> == Flow and Transport Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> == Hydraulic Head, Pressure, and Stress Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis<br /> |}<br /> <br /> == Time Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration and time steps<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time and clock-time controls<br /> |}<br /> <br /> == Hydraulic Coefficients and Other Dimensionless Quantities ==<br /> <br /> The canonical UCUM unit identifier for all quantities in this section is &lt;code&gt;1&lt;/code&gt;. The AOWIS unit suffix is omitted.<br /> <br /> Semantic terms such as &lt;code&gt;ratio&lt;/code&gt;, &lt;code&gt;factor&lt;/code&gt;, &lt;code&gt;coefficient&lt;/code&gt;, &lt;code&gt;multiplier&lt;/code&gt;, and &lt;code&gt;exponent&lt;/code&gt; describe the quantity and are not unit suffixes.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hazen_williams_roughness_coefficient&lt;/code&gt; || Hazen-Williams pipe roughness coefficient || &lt;code&gt;1&lt;/code&gt; || none || EPANET Hazen-Williams roughness<br /> |-<br /> | &lt;code&gt;chezy_manning_roughness_coefficient&lt;/code&gt; || Chezy-Manning pipe roughness coefficient || &lt;code&gt;1&lt;/code&gt; || none || EPANET Chezy-Manning roughness<br /> |-<br /> | &lt;code&gt;minor_loss_coefficient&lt;/code&gt; || Coefficient representing local hydraulic losses || &lt;code&gt;1&lt;/code&gt; || none || Pipe and valve minor loss; TCV setting<br /> |-<br /> | &lt;code&gt;darcy_weisbach_friction_factor&lt;/code&gt; || Darcy-Weisbach friction factor || &lt;code&gt;1&lt;/code&gt; || none || Pipe simulation result<br /> |-<br /> | &lt;code&gt;pump_speed_ratio&lt;/code&gt; || Pump rotational speed relative to nominal or reference speed || &lt;code&gt;1&lt;/code&gt; || none || Pump setting, result, pattern, control, and rule values<br /> |-<br /> | &lt;code&gt;pattern_multiplier&lt;/code&gt; || Factor applied by a hydraulic or energy pattern || &lt;code&gt;1&lt;/code&gt; || none || EPANET pattern factor<br /> |-<br /> | &lt;code&gt;demand_multiplier&lt;/code&gt; || Global factor applied to base demands || &lt;code&gt;1&lt;/code&gt; || none || EPANET demand multiplier<br /> |-<br /> | &lt;code&gt;pressure_exponent&lt;/code&gt; || Exponent used by the pressure-driven demand relation || &lt;code&gt;1&lt;/code&gt; || none || EPANET pressure exponent<br /> |-<br /> | &lt;code&gt;emitter_exponent&lt;/code&gt; || Exponent used by the emitter pressure-flow relation || &lt;code&gt;1&lt;/code&gt; || none || EPANET emitter exponent<br /> |-<br /> | &lt;code&gt;reaction_order&lt;/code&gt; || Order of a bulk, wall, or tank reaction equation || &lt;code&gt;1&lt;/code&gt; || none || EPANET reaction order<br /> |-<br /> | &lt;code&gt;specific_gravity&lt;/code&gt; || Fluid density relative to a defined reference density || &lt;code&gt;1&lt;/code&gt; || none || EPANET specific gravity<br /> |-<br /> | &lt;code&gt;relative_viscosity&lt;/code&gt; || Kinematic viscosity relative to the solver reference || &lt;code&gt;1&lt;/code&gt; || none || EPANET relative viscosity<br /> |-<br /> | &lt;code&gt;relative_diffusivity&lt;/code&gt; || Molecular diffusivity relative to the solver reference || &lt;code&gt;1&lt;/code&gt; || none || EPANET relative diffusivity<br /> |-<br /> | &lt;code&gt;mixing_fraction&lt;/code&gt; || Fraction of tank volume assigned to the applicable mixing zone || &lt;code&gt;1&lt;/code&gt; || none || EPANET tank mixing fraction<br /> |-<br /> | &lt;code&gt;hydraulic_accuracy&lt;/code&gt; || Relative hydraulic convergence criterion || &lt;code&gt;1&lt;/code&gt; || none || EPANET hydraulic accuracy<br /> |-<br /> | &lt;code&gt;hydraulic_damping_limit&lt;/code&gt; || Relative threshold controlling solver damping or status checks || &lt;code&gt;1&lt;/code&gt; || none || EPANET damping limit<br /> |-<br /> | &lt;code&gt;relative_error&lt;/code&gt; || Relative numerical error || &lt;code&gt;1&lt;/code&gt; || none || Hydraulic simulation statistics<br /> |-<br /> | &lt;code&gt;flow_balance_ratio&lt;/code&gt; || Ratio of total outflow to total inflow || &lt;code&gt;1&lt;/code&gt; || none || EPANET flow-balance reporting<br /> |-<br /> | &lt;code&gt;quality_mass_balance_ratio&lt;/code&gt; || Water-quality mass-conservation ratio || &lt;code&gt;1&lt;/code&gt; || none || EPANET quality mass-balance reporting<br /> |}<br /> <br /> == Percentage Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |-<br /> | &lt;code&gt;operating_time_percentage&lt;/code&gt; || Fraction of a reporting period during which equipment operates || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump energy reporting<br /> |-<br /> | &lt;code&gt;demand_reduction_percentage&lt;/code&gt; || Reduction in delivered demand relative to requested demand || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Hydraulic statistics<br /> |-<br /> | &lt;code&gt;leakage_loss_percentage&lt;/code&gt; || Leakage loss relative to total system inflow || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Leakage statistics<br /> |}<br /> <br /> == Reaction and Leakage Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe, and tank first-order bulk reactions<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe first-order wall reactions<br /> |-<br /> | &lt;code&gt;leak_area_per_100m_pipe_length&lt;/code&gt; || Effective leak area assigned per 100 metres of pipe length || square millimetre per 100 metres (mm²/100 m) || &lt;code&gt;mm2/(100.m)&lt;/code&gt; || &lt;code&gt;mm2_per_100m&lt;/code&gt; || EPANET 2.3 FAVAD leak area; EPANET uses 100 project length units and the adapter converts when required&lt;ref name=&quot;EPANET23&quot;&gt;OWA-EPANET 2.3 release notes https://github.com/OpenWaterAnalytics/EPANET/blob/v2.3/ReleaseNotes2_3.md&lt;/ref&gt;<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre of pressure head (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m_head&lt;/code&gt; || EPANET 2.3 FAVAD leak expansion<br /> |}<br /> <br /> == Water Quality Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || Chemical quality input and results<br /> |-<br /> | &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt; || Chemical mass introduced into or transported through the system per unit time || milligram per minute (mg/min) || &lt;code&gt;mg/min&lt;/code&gt; || &lt;code&gt;mg_per_min&lt;/code&gt; || EPANET mass-booster source strength and source mass rate<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> == Power, Energy, and Electrical Quantities ==<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! UCUM Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> The following concepts cannot be assigned one fixed canonical unit until their applicable context has been resolved.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Model Concept !! Context-Dependent Meaning !! Required Representation<br /> |-<br /> | Valve setting || PRV, PSV, and PBV: pressure head; FCV: volumetric flow rate; TCV: minor-loss coefficient; PCV: valve position; GPV: curve reference || Use quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Pump setting || Pump speed relative to nominal speed || Resolve as &lt;code&gt;pump_speed_ratio&lt;/code&gt;<br /> |-<br /> | Control action setting || Quantity supported by the controlled link type || Use the same quantity-specific setting representation as the target link<br /> |-<br /> | Control trigger || Water level, pressure head, elapsed time, or time of day depending on control type || Use quantity-specific trigger representations<br /> |-<br /> | Rule premise value || Quantity selected by the rule variable || Store or resolve the rule variable together with its quantity-specific value<br /> |-<br /> | Rule action setting || Quantity supported by the target link || Use the target link's quantity-specific setting representation<br /> |-<br /> | Initial and simulated quality || Chemical concentration, water age, or source-trace percentage depending on analysis mode || Resolve through the active quality-analysis mode<br /> |-<br /> | Water-quality solver tolerance || Quantity depends on quality-analysis mode || Resolve through the active quality-analysis mode<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate depending on source type || Use a source-type-specific representation<br /> |-<br /> | Reaction coefficient || Dimensions depend on reaction order || Use fixed quantities only for defined fixed-order cases; otherwise retain the reaction order with the coefficient<br /> |-<br /> | Emitter coefficient || In &lt;code&gt;Q = C H^n&lt;/code&gt;, the dimensional meaning of &lt;code&gt;C&lt;/code&gt; depends on &lt;code&gt;n&lt;/code&gt; || Store coefficient and exponent together<br /> |-<br /> | Generic curve coordinates || Quantities depend on curve type || Prefer typed curve structures; genuinely generic curves require explicit quantity metadata<br /> |-<br /> | Report thresholds || Quantity depends on the corresponding report field || Associate each threshold with the report field's measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate interpretation depends on the associated map configuration || Resolve to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Monetary Values ==<br /> <br /> Monetary values that depend on a currency MUST identify that currency using its ISO 4217 alphabetic code or by reference to a configured currency carrying that code.&lt;ref name=&quot;ISO4217&quot;&gt;ISO 4217 currency codes https://www.iso.org/iso-4217-currency-codes.html&lt;/ref&gt;<br /> <br /> Where a monetary value is normalized by a physical quantity, the physical quantity uses the canonical unit defined by this registry.<br /> <br /> For example:<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Concept !! Physical Denominator<br /> |-<br /> | Energy price || kilowatt-hour (kWh)<br /> |-<br /> | Demand charge || kilowatt (kW)<br /> |-<br /> | Daily cost rate || day (d)<br /> |}<br /> <br /> == AOWIS Model and Backend Mapping ==<br /> <br /> Fixed-schema Model fields encode their canonical unit through the schema and, where applicable, the AOWIS identifier suffix.<br /> <br /> Backend-selected unit systems MUST NOT alter those field semantics.<br /> <br /> The EPANET adapter converts backend values whenever the EPANET project representation differs from the canonical AOWIS representation. Relevant mappings include:<br /> <br /> * volumetric flow rate → &lt;code&gt;m3/h&lt;/code&gt;;<br /> * length and hydraulic head → &lt;code&gt;m&lt;/code&gt;;<br /> * link diameter → &lt;code&gt;mm&lt;/code&gt;;<br /> * tank diameter → &lt;code&gt;m&lt;/code&gt;;<br /> * Darcy-Weisbach roughness → &lt;code&gt;mm&lt;/code&gt;;<br /> * head-loss gradient → &lt;code&gt;m/km&lt;/code&gt;;<br /> * leakage area → &lt;code&gt;mm2/(100.m)&lt;/code&gt;;<br /> * leakage expansion → &lt;code&gt;mm2/m&lt;/code&gt; of pressure head;<br /> * energy intensity → &lt;code&gt;kW.h/m3&lt;/code&gt;;<br /> * chemical concentration → &lt;code&gt;mg/L&lt;/code&gt;;<br /> * chemical mass flow rate → &lt;code&gt;mg/min&lt;/code&gt;.<br /> <br /> == References ==<br /> <br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=675 2026-08-18T15:20:18Z

<p>Samuel: </p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Canonical_Units]]<br /> <br /> AOWIS uses a canonical representation for measurement quantities. Each measurement quantity has one canonical unit defined in [[Measurement:Canonical_Units|Canonical Units]].<br /> <br /> Canonical units are selected individually based on SI, established engineering practice, numerical practicality, and interoperability. Values MAY use other units at system boundaries and in user interfaces, but the authoritative AOWIS representation remains canonical.<br /> <br /> == Purpose ==<br /> <br /> This specification defines how measurement quantities, values, units, conversions, and measurement-related numeric data are represented and handled by AOWIS.<br /> <br /> A single canonical representation:<br /> <br /> * provides an unambiguous data contract between AOWIS components;<br /> * prevents backend- or locale-specific units from leaking into the domain model;<br /> * simplifies validation, comparison, computation, serialization, and testing;<br /> * allows user interfaces and external systems to use alternative units without changing the authoritative representation.<br /> <br /> The canonical measurement quantities and units themselves are defined in [[Measurement:Canonical_Units]].<br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; Measurement quantity<br /> : A defined physical or engineering quantity being represented, such as volumetric flow rate, pressure head, power, or efficiency.<br /> <br /> ; Canonical unit<br /> : The single unit assigned by AOWIS to a measurement quantity for authoritative representation.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : A numerical value and unit received from a user, device, file, backend, component, or external system before conversion into the canonical AOWIS representation.<br /> <br /> ; Unit identifier<br /> : The machine-readable identifier of a unit. AOWIS uses UCUM for physical unit identifiers.<br /> <br /> ; Fixed-schema measurement field<br /> : A field whose measurement quantity and canonical unit are defined by the schema.<br /> <br /> ; Context-dependent measurement value<br /> : A value whose measurement quantity depends on another field, enum, object type, equation, or operating mode.<br /> <br /> == Requirements ==<br /> <br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing measurement quantities within the AOWIS domain model MUST be represented using the canonical unit defined for the measurement quantity.<br /> <br /> REQ-MEAS-002: Each fixed or resolved measurement quantity MUST be assigned exactly one canonical unit.<br /> <br /> REQ-MEAS-003: Measurement quantities with different meanings MUST remain distinct even when they use the same canonical unit.<br /> <br /> REQ-MEAS-004: Physical unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-005: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> <br /> REQ-MEAS-006: Dimensionless physical measurement quantities MUST use the UCUM unit identifier &quot;1&quot;. A fixed-schema field with canonical unit &quot;1&quot; MAY omit a unit suffix when its field name unambiguously identifies the quantity.<br /> <br /> REQ-MEAS-007: Numeric values that are not measurement quantities MUST NOT be assigned measurement units solely because they are numeric.<br /> <br /> REQ-MEAS-008: A value whose measurement quantity depends on another field, enum, object type, equation, or operating mode MUST be represented using quantity-specific fields or a discriminated structure that identifies the resolved quantity.<br /> <br /> REQ-MEAS-009: An equation coefficient whose dimensions depend on configurable equation parameters MUST retain the parameters required to determine its dimensional meaning and MUST NOT be represented using a misleading fixed unit.<br /> <br /> REQ-MEAS-010: Values entering the AOWIS domain model in non-canonical units MUST be converted to their defined canonical units at the applicable system boundary. Values leaving AOWIS MAY be converted to the representation required by the receiving system or interface.<br /> <br /> REQ-MEAS-011: Conversion artifacts, rounding errors, and precision loss introduced by an implementation MUST NOT exceed the documented precision of the measurement.<br /> <br /> REQ-MEAS-012: Original source values and unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-013: Monetary values that depend on a currency MUST identify that currency using its ISO 4217 alphabetic code or by reference to a configured currency carrying that code.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UI-001: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a measurement quantity.<br /> <br /> REQ-MEAS-UI-002: User interfaces MAY display measurement values in supported non-canonical units.<br /> <br /> REQ-MEAS-UI-003: User interfaces accepting values in non-canonical units MUST convert the entered value to its canonical unit before it enters the AOWIS domain model.<br /> <br /> REQ-MEAS-UI-004: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Interpretation of the Requirements ==<br /> <br /> ''This section is informative. The normative requirements above remain authoritative.''<br /> <br /> A canonical unit belongs to a '''measurement quantity''', not merely to a numeric data type. Two quantities can therefore use the same unit while remaining semantically different. For example, elevation, hydraulic head, pressure head, and water level are all expressed in metres but represent different quantities.<br /> <br /> Dimensionless physical quantities remain measurement quantities. Examples include demand multipliers, pump speed ratios, hydraulic coefficients, and exponents. Their canonical UCUM unit is &lt;code&gt;1&lt;/code&gt;. Fixed-schema fields normally express their meaning through the field name and do not need an artificial unit suffix such as &lt;code&gt;_1&lt;/code&gt;.<br /> <br /> Conversely, a number is not automatically a measurement. Counts, indices, priorities, identifiers, decimal precision settings, and similar values do not require measurement units.<br /> <br /> Some values cannot be assigned a unit until their context is known. A valve setting, for example, may represent pressure head, volumetric flow rate, valve position, a loss coefficient, or another quantity depending on the valve type. Such values must therefore be represented so that their actual measurement quantity is unambiguous.<br /> <br /> The same principle applies to control values, rule values, water-quality values, report thresholds, generic curve coordinates, and similar context-dependent data.<br /> <br /> Equation coefficients require additional care when their dimensional meaning depends on configurable equation parameters. For example, in an emitter relation<br /> <br /> &lt;pre&gt;<br /> Q = C H^n<br /> &lt;/pre&gt;<br /> <br /> the dimensional meaning of &lt;code&gt;C&lt;/code&gt; depends on the exponent &lt;code&gt;n&lt;/code&gt;. The coefficient and the parameters required to interpret it must therefore remain associated.<br /> <br /> Alternative backend, import, export, user-selected, and display units do not change the canonical AOWIS representation. Conversion occurs at the boundary where the alternative representation enters or leaves AOWIS.<br /> <br /> === Examples ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Value !! Interpretation<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate = 12.5 m3/h&lt;/code&gt; || Measurement quantity with canonical unit &lt;code&gt;m3/h&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;demand_multiplier = 1.2&lt;/code&gt; || Dimensionless measurement quantity with canonical UCUM unit &lt;code&gt;1&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;rule_priority = 5&lt;/code&gt; || Numeric value that is not a measurement quantity<br /> |-<br /> | FCV setting &lt;code&gt;20 m3/h&lt;/code&gt; || Setting resolved to volumetric flow rate<br /> |-<br /> | PRV setting &lt;code&gt;30 m&lt;/code&gt; || Setting resolved to pressure head<br /> |}<br /> <br /> == Boundary Conversion ==<br /> <br /> The AOWIS domain model uses canonical units independently of the unit systems used by backends, files, external systems, devices, or user interfaces.<br /> <br /> An adapter or interface is responsible for converting values whenever its representation differs from the canonical AOWIS representation.<br /> <br /> For example, an EPANET project MAY use any EPANET-supported flow or pressure unit system. The EPANET adapter converts those values to and from the canonical quantities defined in [[Measurement:Canonical_Units]].<br /> <br /> A backend configuration option that selects a backend unit system does not alter the canonical AOWIS data contract.<br /> <br /> == Fixed and Dynamic Schema Values ==<br /> <br /> For a fixed-schema field, the measurement quantity and canonical unit MAY be defined entirely by the schema.<br /> <br /> For example:<br /> <br /> &lt;pre&gt;<br /> flow_m3_per_h<br /> pressure_head_m<br /> power_kw<br /> &lt;/pre&gt;<br /> <br /> do not require a separate unit property when their schema definition unambiguously establishes the measurement quantity and unit.<br /> <br /> Generic or dynamically typed measurement values MUST identify or resolve to their measurement quantity. Where the unit is represented explicitly, the canonical UCUM identifier defined in [[Measurement:Canonical_Units]] MUST be used.<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the Model MUST follow this specification and the canonical quantity registry in [[Measurement:Canonical_Units]].<br /> <br /> == References ==<br /> <br /> &lt;references /&gt;<br /> <br /> * Unified Code for Units of Measure (UCUM)&lt;ref name=&quot;UCUM&quot;&gt;https://ucum.org&lt;/ref&gt;<br /> * International Bureau of Weights and Measures (BIPM), International System of Units (SI)&lt;ref name=&quot;BIPM&quot;&gt;https://www.bipm.org/en/measurement-units&lt;/ref&gt;<br /> * ISO 4217 currency codes&lt;ref name=&quot;ISO4217&quot;&gt;https://www.iso.org/iso-4217-currency-codes.html&lt;/ref&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=674 2026-08-18T15:05:49Z

<p>Samuel: </p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for machine-readable physical unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> Currencies are not represented as UCUM units in AOWIS. Monetary values use currencies identified by ISO 4217&lt;ref name=&quot;ISO4217&quot;&gt;ISO 4217 Currency Codes https://www.iso.org/iso-4217-currency-codes.html&lt;/ref&gt; and follow the monetary-value rules defined on this page.<br /> <br /> == General Rules ==<br /> <br /> * All physical unit identifiers MUST conform to UCUM.<br /> * Each fixed or resolved physical measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> * A numeric value is not necessarily a measurement quantity. Counts, indices, priorities, precision values, identifiers, and similar non-measurement numbers do not receive UCUM unit identifiers merely because they are numeric.<br /> * Dimensionless physical quantities use the UCUM unity unit &lt;code&gt;1&lt;/code&gt;. Fixed-schema fields whose canonical unit is &lt;code&gt;1&lt;/code&gt; do not require an AOWIS unit suffix when the field name unambiguously identifies the dimensionless quantity.<br /> * A numeric value whose physical quantity depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a misleading fixed unit. It MUST be resolved through a quantity-specific field or discriminated structure.<br /> * Equation coefficients whose dimensions depend on a configurable non-integer exponent MUST be stored together with the equation parameters that determine their dimensional meaning and MUST NOT be represented as if they had one fixed standalone UCUM unit.<br /> * Backend-native, imported, display, and user-selected units MUST be converted to the canonical AOWIS representation at system boundaries unless the backend-native representation is itself the canonical AOWIS representation.<br /> * Currencies and exchange rates are outside UCUM unit conversion. Monetary values MUST identify or reference their ISO 4217 currency.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All physical unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each fixed or resolved physical measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> <br /> REQ-MEAS-UNI-005: Dimensionless physical measurement quantities MUST use the UCUM unit identifier &quot;1&quot;. A fixed-schema field with canonical unit &quot;1&quot; MAY omit a unit suffix when its field name unambiguously identifies the quantity.<br /> <br /> REQ-MEAS-UNI-006: Numeric values that are not physical measurement quantities MUST NOT be assigned UCUM unit identifiers solely because they are numeric.<br /> <br /> REQ-MEAS-UNI-007: A value whose physical quantity depends on another field, enum, object type, equation, or operating mode MUST be represented using quantity-specific fields or a discriminated structure that identifies the resolved quantity.<br /> <br /> REQ-MEAS-UNI-008: An equation coefficient whose dimensions depend on a configurable non-integer exponent MUST be stored together with the parameters that determine its dimensional meaning and MUST NOT be assigned a misleading fixed standalone UCUM unit.<br /> <br /> REQ-MEAS-UNI-009: Non-canonical backend, import, display, or user-selected units MUST be converted to the canonical AOWIS representation at system boundaries.<br /> <br /> REQ-MEAS-UNI-010: Currencies MUST NOT be represented as UCUM units in AOWIS. Monetary values MUST identify or reference a currency using its ISO 4217 currency identifier.<br /> &lt;/pre&gt;<br /> <br /> == Interpretation of the Requirements ==<br /> <br /> ''This section is informative. The normative requirements above remain authoritative.''<br /> <br /> The requirements distinguish physical measurement quantities from other numeric values and from monetary values. Physical measurement quantities use canonical UCUM units, including UCUM &lt;code&gt;1&lt;/code&gt; for dimensionless physical quantities. Numeric values such as counts, priorities, indices, or precision settings are not measurement quantities merely because they are numeric and therefore do not require UCUM units.<br /> <br /> A measurement value whose physical quantity depends on another field, object type, operating mode, or equation must first be resolved to a specific measurement quantity. Once resolved, that quantity uses the canonical UCUM unit defined by AOWIS. This applies, for example, to valve settings, control and rule values, water-quality values, report thresholds, and similar context-dependent fields.<br /> <br /> Backend, import, export, user-selected, and display units do not change the canonical AOWIS representation. Conversion to and from non-canonical units occurs at system boundaries.<br /> <br /> Equation coefficients whose dimensions depend on configurable parameters, such as an arbitrary emitter exponent, must retain the parameters required to interpret their dimensional meaning and must not be assigned a misleading fixed unit.<br /> <br /> Monetary values are outside the UCUM measurement-unit system. Their currency is identified or referenced using ISO 4217, while any physical denominator such as kilowatt-hour or kilowatt remains governed by this measurement standard.<br /> <br /> === Examples ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Example !! Interpretation<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate = 12.5 m3/h&lt;/code&gt; || Physical measurement; canonical UCUM unit &lt;code&gt;m3/h&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;demand_multiplier = 1.2&lt;/code&gt; || Dimensionless physical measurement; canonical UCUM unit &lt;code&gt;1&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;rule_priority = 5&lt;/code&gt; || Numeric value, not a physical measurement; no UCUM unit<br /> |-<br /> | &lt;code&gt;energy_price = 0.25 EUR/kWh&lt;/code&gt; || &lt;code&gt;EUR&lt;/code&gt; is ISO 4217 currency information; &lt;code&gt;kW.h&lt;/code&gt; is the physical unit in the denominator<br /> |-<br /> | FCV setting = &lt;code&gt;20 m3/h&lt;/code&gt;; PRV setting = &lt;code&gt;30 m&lt;/code&gt; || Both are settings, but they resolve to different measurement quantities and therefore different canonical units<br /> |}<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier assigned to a measurement quantity is authoritative whenever a unit identifier is represented in serialization or data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case. A quantity-specific semantic qualifier MAY be included where a literal unit-only suffix would be ambiguous or misleading; for example, &lt;code&gt;mm2_per_m_head&lt;/code&gt; makes explicit that the denominator represents pressure head.<br /> <br /> For fixed-schema measurement fields, the measurement quantity and canonical unit MAY be defined normatively by the schema and represented through the field name and its AOWIS identifier suffix. Such fields do not require a separate unit-identifier property.<br /> <br /> Dimensionless fixed-schema fields whose canonical unit is &lt;code&gt;1&lt;/code&gt; normally omit a unit suffix. Semantic words such as &lt;code&gt;ratio&lt;/code&gt;, &lt;code&gt;factor&lt;/code&gt;, &lt;code&gt;coefficient&lt;/code&gt;, &lt;code&gt;multiplier&lt;/code&gt;, and &lt;code&gt;exponent&lt;/code&gt; describe the quantity and are not unit suffixes.<br /> <br /> When a unit identifier is represented explicitly, it MUST use the canonical UCUM identifier assigned to the measurement quantity. The AOWIS identifier suffix is a technical field-naming convention and is not itself a UCUM unit identifier.<br /> <br /> Generic or dynamically typed physical measurement values MUST explicitly identify their resolved measurement quantity and canonical UCUM unit and MUST NOT rely solely on a field-name suffix.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Distance Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |-<br /> | &lt;code&gt;darcy_weisbach_roughness_height&lt;/code&gt; || Absolute pipe-wall roughness height used by the Darcy-Weisbach head-loss formulation || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET Darcy-Weisbach pipe roughness<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |-<br /> | &lt;code&gt;local_x&lt;/code&gt; || X coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local engineering coordinates when the local coordinate system is defined in metres<br /> |-<br /> | &lt;code&gt;local_y&lt;/code&gt; || Y coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local engineering coordinates when the local coordinate system is defined in metres<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Hydraulic Coefficients and Other Dimensionless Quantities ===<br /> <br /> The canonical UCUM unit identifier for the quantities in this section is &lt;code&gt;1&lt;/code&gt;. The AOWIS unit suffix is intentionally omitted. Semantic field-name components such as &lt;code&gt;ratio&lt;/code&gt;, &lt;code&gt;factor&lt;/code&gt;, &lt;code&gt;coefficient&lt;/code&gt;, &lt;code&gt;multiplier&lt;/code&gt;, and &lt;code&gt;exponent&lt;/code&gt; remain part of the quantity name where useful.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hazen_williams_roughness_coefficient&lt;/code&gt; || Empirical pipe roughness coefficient used by the Hazen-Williams head-loss formulation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET Hazen-Williams pipe roughness<br /> |-<br /> | &lt;code&gt;chezy_manning_roughness_coefficient&lt;/code&gt; || Empirical pipe roughness coefficient used by the Chezy-Manning head-loss formulation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET Chezy-Manning pipe roughness<br /> |-<br /> | &lt;code&gt;minor_loss_coefficient&lt;/code&gt; || Dimensionless coefficient representing local hydraulic losses through fittings, valves, or other components || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || Pipe and valve minor-loss coefficient; TCV setting<br /> |-<br /> | &lt;code&gt;darcy_weisbach_friction_factor&lt;/code&gt; || Dimensionless friction factor used in Darcy-Weisbach head-loss calculations || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || Pipe simulation friction factor<br /> |-<br /> | &lt;code&gt;pump_speed_ratio&lt;/code&gt; || Pump rotational speed relative to its nominal or reference speed || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || Pump initial speed, simulated speed, pattern-modified speed, and pump control/rule settings<br /> |-<br /> | &lt;code&gt;pattern_multiplier&lt;/code&gt; || Dimensionless factor applied by a hydraulic or energy pattern || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET pattern factors<br /> |-<br /> | &lt;code&gt;demand_multiplier&lt;/code&gt; || Global factor applied to base demands || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET demand multiplier<br /> |-<br /> | &lt;code&gt;pressure_exponent&lt;/code&gt; || Exponent used by the pressure-driven demand relation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET pressure exponent<br /> |-<br /> | &lt;code&gt;emitter_exponent&lt;/code&gt; || Exponent used by the emitter pressure-flow relation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET emitter exponent<br /> |-<br /> | &lt;code&gt;reaction_order&lt;/code&gt; || Exponent defining the order of a bulk, wall, or tank reaction equation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET bulk, wall, and tank reaction orders<br /> |-<br /> | &lt;code&gt;specific_gravity&lt;/code&gt; || Fluid density relative to the reference density used by the hydraulic solver || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET specific gravity<br /> |-<br /> | &lt;code&gt;relative_viscosity&lt;/code&gt; || Fluid kinematic viscosity relative to the solver's reference viscosity || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET relative viscosity<br /> |-<br /> | &lt;code&gt;relative_diffusivity&lt;/code&gt; || Molecular diffusivity relative to the solver's reference diffusivity || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET relative diffusivity<br /> |-<br /> | &lt;code&gt;mixing_fraction&lt;/code&gt; || Fraction of tank volume assigned to the mixing zone in applicable tank mixing models || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET tank mixing fraction<br /> |-<br /> | &lt;code&gt;hydraulic_accuracy&lt;/code&gt; || Relative convergence criterion used by the hydraulic solver || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET hydraulic accuracy<br /> |-<br /> | &lt;code&gt;hydraulic_damping_limit&lt;/code&gt; || Relative accuracy threshold at which hydraulic solution damping/status checks are activated || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET damping limit<br /> |-<br /> | &lt;code&gt;relative_error&lt;/code&gt; || Relative numerical error reported by a solver or conformance check || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || Hydraulic simulation statistics<br /> |-<br /> | &lt;code&gt;flow_balance_ratio&lt;/code&gt; || Ratio of total outflow to total inflow || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET flow-balance reporting<br /> |-<br /> | &lt;code&gt;quality_mass_balance_ratio&lt;/code&gt; || Ratio expressing conservation of transported water-quality mass || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET water-quality mass-balance statistic<br /> |}<br /> <br /> === Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |-<br /> | &lt;code&gt;operating_time_percentage&lt;/code&gt; || Fraction of a reporting period during which equipment is operating, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump energy reporting time online<br /> |-<br /> | &lt;code&gt;demand_reduction_percentage&lt;/code&gt; || Reduction in delivered demand relative to requested demand, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Hydraulic simulation statistics<br /> |-<br /> | &lt;code&gt;leakage_loss_percentage&lt;/code&gt; || Leakage loss relative to total system inflow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET leakage-loss statistic<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_100m_pipe_length&lt;/code&gt; || Effective leak area assigned per 100 metres of pipe length || square millimetre per 100 metres (mm²/100 m) || &lt;code&gt;mm2/(100.m)&lt;/code&gt; || &lt;code&gt;mm2_per_100m&lt;/code&gt; || EPANET 2.3 FAVAD leak area; EPANET defines the native value per 100 project length units, so non-metric projects require conversion at the adapter boundary&lt;ref name=&quot;EPANET23&quot;&gt;OWA-EPANET 2.3 release notes https://github.com/OpenWaterAnalytics/EPANET/blob/v2.3/ReleaseNotes2_3.md&lt;/ref&gt;<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre of pressure head (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m_head&lt;/code&gt; || EPANET 2.3 FAVAD leak expansion; non-metric projects require pressure-head conversion at the adapter boundary&lt;ref name=&quot;EPANET23&quot; /&gt;<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input, reaction limiting concentration, quality-source concentration, and simulation results<br /> |-<br /> | &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt; || Chemical mass introduced into or transported through the system per unit time || milligram per minute (mg/min) || &lt;code&gt;mg/min&lt;/code&gt; || &lt;code&gt;mg_per_min&lt;/code&gt; || EPANET mass-booster source strength and reported source mass rate when chemical concentration is canonicalized to mg/L<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting; canonical replacement for backend-dependent power-per-flow-unit values<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Monetary Values and Currencies ==<br /> <br /> Currencies are identifiers for monetary value and are not physical units in the AOWIS measurement system. AOWIS therefore does not encode currencies or currency compounds as UCUM unit identifiers.<br /> <br /> A monetary value MUST identify or reference a currency definition whose identifier is the ISO 4217 alphabetic currency code. The currency definition MAY be managed by the AOWIS Controller or another authoritative subsystem.<br /> <br /> AOWIS MAY support multiple currencies simultaneously. Exchange rates, exchange-rate timestamps, conversion policy, rounding policy, and accounting policy belong to the currency/controller subsystem and MUST NOT be treated as physical unit conversions.<br /> <br /> Where a monetary quantity is normalized by a physical quantity, the physical denominator MUST use the canonical AOWIS physical unit. This yields the following canonical monetary semantics:<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Monetary Quantity Identifier !! Definition !! Currency Representation !! Canonical Physical Denominator !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;energy_price&lt;/code&gt; || Monetary price charged per unit of electrical energy || ISO 4217 currency reference || kilowatt-hour (kWh) || Global and pump-specific energy price<br /> |-<br /> | &lt;code&gt;demand_charge_rate&lt;/code&gt; || Monetary demand charge per unit of peak power || ISO 4217 currency reference || kilowatt (kW) || Global demand charge<br /> |-<br /> | &lt;code&gt;daily_cost_rate&lt;/code&gt; || Monetary cost accumulated or averaged per day || ISO 4217 currency reference || day (d) || Average pump cost, energy cost, demand charge, and total cost reporting<br /> |}<br /> <br /> A monetary value MUST NOT be interpreted without its currency reference. Two monetary values denominated in different currencies MUST NOT be compared, added, or aggregated without an explicit currency conversion performed by the currency/controller subsystem.<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single fixed canonical unit or AOWIS identifier suffix before that context has been resolved.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity. Once resolved to a defined measurement quantity, the value MUST use that quantity's canonical AOWIS unit.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || PRV, PSV, and PBV settings are pressure head; FCV setting is volumetric flow rate; TCV setting is a minor-loss coefficient; PCV setting is valve position; GPV uses a curve reference rather than a numeric physical setting || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Pump setting || Pump speed setting is a pump-speed ratio rather than a flow, head, or percentage || Represent pump settings explicitly as &lt;code&gt;pump_speed_ratio&lt;/code&gt;<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Water-quality solver tolerance || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Bind the tolerance to the selected quality-analysis mode and represent it using that mode's canonical quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Reported source mass rate || Chemical mass flow rate in chemical-quality analysis; other quality-analysis modes must not be mislabeled as chemical mass || Resolve the result through the active quality-analysis mode before assigning &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt;<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use first-order fixed quantities only when the reaction order is exactly first order; otherwise store the coefficient together with reaction order in a discriminated reaction-coefficient structure<br /> |-<br /> | Roughness-correlation reaction parameter || The parameter belongs to the configured wall-reaction correlation model and does not have a universally valid standalone measurement unit || Store it as part of the applicable reaction model rather than assigning a guessed fixed unit<br /> |-<br /> | Emitter coefficient || In the canonical AOWIS emitter equation &lt;code&gt;Q = C H^n&lt;/code&gt;, &lt;code&gt;Q&lt;/code&gt; is volumetric flow rate in m³/h, &lt;code&gt;H&lt;/code&gt; is pressure head in m, and &lt;code&gt;n&lt;/code&gt; is the dimensionless emitter exponent; the dimensional meaning of &lt;code&gt;C&lt;/code&gt; therefore depends on &lt;code&gt;n&lt;/code&gt; || Store the coefficient and exponent together in a dedicated emitter relation. The coefficient MUST NOT claim one fixed standalone UCUM unit for arbitrary non-integer &lt;code&gt;n&lt;/code&gt;<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known; only genuinely generic curves may carry explicit quantity metadata<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity and canonical unit<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration; &lt;code&gt;None&lt;/code&gt; does not define a physical unit || Convert to an explicitly identified geographic, projected, or local coordinate representation before treating the coordinates as physical measurements<br /> |}<br /> <br /> == Boundary Conversion Rules ==<br /> <br /> AOWIS canonical units define the public data contract. Backend-selected unit systems MUST NOT leak into fixed-schema AOWIS measurement fields.<br /> <br /> The EPANET adapter MUST convert EPANET values to and from the canonical AOWIS units whenever EPANET's selected unit system differs from the canonical AOWIS representation.<br /> <br /> This includes, where applicable:<br /> <br /> * volumetric flow rates to and from &lt;code&gt;m3/h&lt;/code&gt;;<br /> * lengths and hydraulic heads to and from &lt;code&gt;m&lt;/code&gt;;<br /> * link diameters to and from &lt;code&gt;mm&lt;/code&gt;;<br /> * tank diameters to and from &lt;code&gt;m&lt;/code&gt;;<br /> * Darcy-Weisbach roughness to and from &lt;code&gt;mm&lt;/code&gt;;<br /> * head-loss gradients to and from &lt;code&gt;m/km&lt;/code&gt;;<br /> * leakage area to and from &lt;code&gt;mm2/(100.m)&lt;/code&gt;;<br /> * leakage expansion to and from &lt;code&gt;mm2/m&lt;/code&gt; of pressure head;<br /> * energy-use reporting to &lt;code&gt;kW.h/m3&lt;/code&gt; where the backend reports power per selected flow unit;<br /> * chemical concentration to &lt;code&gt;mg/L&lt;/code&gt; when chemical-quality support is active;<br /> * chemical mass flow rate to &lt;code&gt;mg/min&lt;/code&gt; when chemical-quality support is active.<br /> <br /> A backend configuration value that selects how the backend displays or interprets units is not itself a substitute for unit information in the AOWIS data contract.<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Fixed-schema fields encode their canonical unit through the normative schema and, where applicable, the AOWIS identifier suffix. Dimensionless fixed-schema fields with UCUM unit &lt;code&gt;1&lt;/code&gt; may omit a unit suffix when their quantity is unambiguous. Generic or dynamically typed physical measurement values carry or resolve to an explicit canonical UCUM unit identifier.<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.<br /> <br /> Monetary fields defined by the model MUST identify or reference an ISO 4217 currency and MUST follow the monetary-value rules on this page.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=673 2026-08-18T10:13:57Z

<p>Samuel: </p> <hr /> <div>* Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for machine-readable physical unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> Currencies are not represented as UCUM units in AOWIS. Monetary values use currencies identified by ISO 4217&lt;ref name=&quot;ISO4217&quot;&gt;ISO 4217 Currency Codes https://www.iso.org/iso-4217-currency-codes.html&lt;/ref&gt; and follow the monetary-value rules defined on this page.<br /> <br /> == General Rules ==<br /> <br /> * All physical unit identifiers MUST conform to UCUM.<br /> * Each fixed or resolved physical measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> * A numeric value is not necessarily a measurement quantity. Counts, indices, priorities, precision values, identifiers, and similar non-measurement numbers do not receive UCUM unit identifiers merely because they are numeric.<br /> * Dimensionless physical quantities use the UCUM unity unit &lt;code&gt;1&lt;/code&gt;. Fixed-schema fields whose canonical unit is &lt;code&gt;1&lt;/code&gt; do not require an AOWIS unit suffix when the field name unambiguously identifies the dimensionless quantity.<br /> * A numeric value whose physical quantity depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a misleading fixed unit. It MUST be resolved through a quantity-specific field or discriminated structure.<br /> * Equation coefficients whose dimensions depend on a configurable non-integer exponent MUST be stored together with the equation parameters that determine their dimensional meaning and MUST NOT be represented as if they had one fixed standalone UCUM unit.<br /> * Backend-native, imported, display, and user-selected units MUST be converted to the canonical AOWIS representation at system boundaries unless the backend-native representation is itself the canonical AOWIS representation.<br /> * Currencies and exchange rates are outside UCUM unit conversion. Monetary values MUST identify or reference their ISO 4217 currency.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All physical unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each fixed or resolved physical measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> <br /> REQ-MEAS-UNI-005: Dimensionless physical measurement quantities MUST use the UCUM unit identifier &quot;1&quot;. A fixed-schema field with canonical unit &quot;1&quot; MAY omit a unit suffix when its field name unambiguously identifies the quantity.<br /> <br /> REQ-MEAS-UNI-006: Numeric values that are not physical measurement quantities MUST NOT be assigned UCUM unit identifiers solely because they are numeric.<br /> <br /> REQ-MEAS-UNI-007: A value whose physical quantity depends on another field, enum, object type, equation, or operating mode MUST be represented using quantity-specific fields or a discriminated structure that identifies the resolved quantity.<br /> <br /> REQ-MEAS-UNI-008: An equation coefficient whose dimensions depend on a configurable non-integer exponent MUST be stored together with the parameters that determine its dimensional meaning and MUST NOT be assigned a misleading fixed standalone UCUM unit.<br /> <br /> REQ-MEAS-UNI-009: Non-canonical backend, import, display, or user-selected units MUST be converted to the canonical AOWIS representation at system boundaries.<br /> <br /> REQ-MEAS-UNI-010: Currencies MUST NOT be represented as UCUM units in AOWIS. Monetary values MUST identify or reference a currency using its ISO 4217 currency identifier.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier assigned to a measurement quantity is authoritative whenever a unit identifier is represented in serialization or data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case. A quantity-specific semantic qualifier MAY be included where a literal unit-only suffix would be ambiguous or misleading; for example, &lt;code&gt;mm2_per_m_head&lt;/code&gt; makes explicit that the denominator represents pressure head.<br /> <br /> For fixed-schema measurement fields, the measurement quantity and canonical unit MAY be defined normatively by the schema and represented through the field name and its AOWIS identifier suffix. Such fields do not require a separate unit-identifier property.<br /> <br /> Dimensionless fixed-schema fields whose canonical unit is &lt;code&gt;1&lt;/code&gt; normally omit a unit suffix. Semantic words such as &lt;code&gt;ratio&lt;/code&gt;, &lt;code&gt;factor&lt;/code&gt;, &lt;code&gt;coefficient&lt;/code&gt;, &lt;code&gt;multiplier&lt;/code&gt;, and &lt;code&gt;exponent&lt;/code&gt; describe the quantity and are not unit suffixes.<br /> <br /> When a unit identifier is represented explicitly, it MUST use the canonical UCUM identifier assigned to the measurement quantity. The AOWIS identifier suffix is a technical field-naming convention and is not itself a UCUM unit identifier.<br /> <br /> Generic or dynamically typed physical measurement values MUST explicitly identify their resolved measurement quantity and canonical UCUM unit and MUST NOT rely solely on a field-name suffix.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Distance Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |-<br /> | &lt;code&gt;darcy_weisbach_roughness_height&lt;/code&gt; || Absolute pipe-wall roughness height used by the Darcy-Weisbach head-loss formulation || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET Darcy-Weisbach pipe roughness<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |-<br /> | &lt;code&gt;local_x&lt;/code&gt; || X coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local engineering coordinates when the local coordinate system is defined in metres<br /> |-<br /> | &lt;code&gt;local_y&lt;/code&gt; || Y coordinate within an explicitly defined local engineering coordinate system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Local engineering coordinates when the local coordinate system is defined in metres<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Hydraulic Coefficients and Other Dimensionless Quantities ===<br /> <br /> The canonical UCUM unit identifier for the quantities in this section is &lt;code&gt;1&lt;/code&gt;. The AOWIS unit suffix is intentionally omitted. Semantic field-name components such as &lt;code&gt;ratio&lt;/code&gt;, &lt;code&gt;factor&lt;/code&gt;, &lt;code&gt;coefficient&lt;/code&gt;, &lt;code&gt;multiplier&lt;/code&gt;, and &lt;code&gt;exponent&lt;/code&gt; remain part of the quantity name where useful.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hazen_williams_roughness_coefficient&lt;/code&gt; || Empirical pipe roughness coefficient used by the Hazen-Williams head-loss formulation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET Hazen-Williams pipe roughness<br /> |-<br /> | &lt;code&gt;chezy_manning_roughness_coefficient&lt;/code&gt; || Empirical pipe roughness coefficient used by the Chezy-Manning head-loss formulation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET Chezy-Manning pipe roughness<br /> |-<br /> | &lt;code&gt;minor_loss_coefficient&lt;/code&gt; || Dimensionless coefficient representing local hydraulic losses through fittings, valves, or other components || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || Pipe and valve minor-loss coefficient; TCV setting<br /> |-<br /> | &lt;code&gt;darcy_weisbach_friction_factor&lt;/code&gt; || Dimensionless friction factor used in Darcy-Weisbach head-loss calculations || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || Pipe simulation friction factor<br /> |-<br /> | &lt;code&gt;pump_speed_ratio&lt;/code&gt; || Pump rotational speed relative to its nominal or reference speed || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || Pump initial speed, simulated speed, pattern-modified speed, and pump control/rule settings<br /> |-<br /> | &lt;code&gt;pattern_multiplier&lt;/code&gt; || Dimensionless factor applied by a hydraulic or energy pattern || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET pattern factors<br /> |-<br /> | &lt;code&gt;demand_multiplier&lt;/code&gt; || Global factor applied to base demands || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET demand multiplier<br /> |-<br /> | &lt;code&gt;pressure_exponent&lt;/code&gt; || Exponent used by the pressure-driven demand relation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET pressure exponent<br /> |-<br /> | &lt;code&gt;emitter_exponent&lt;/code&gt; || Exponent used by the emitter pressure-flow relation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET emitter exponent<br /> |-<br /> | &lt;code&gt;reaction_order&lt;/code&gt; || Exponent defining the order of a bulk, wall, or tank reaction equation || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET bulk, wall, and tank reaction orders<br /> |-<br /> | &lt;code&gt;specific_gravity&lt;/code&gt; || Fluid density relative to the reference density used by the hydraulic solver || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET specific gravity<br /> |-<br /> | &lt;code&gt;relative_viscosity&lt;/code&gt; || Fluid kinematic viscosity relative to the solver's reference viscosity || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET relative viscosity<br /> |-<br /> | &lt;code&gt;relative_diffusivity&lt;/code&gt; || Molecular diffusivity relative to the solver's reference diffusivity || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET relative diffusivity<br /> |-<br /> | &lt;code&gt;mixing_fraction&lt;/code&gt; || Fraction of tank volume assigned to the mixing zone in applicable tank mixing models || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET tank mixing fraction<br /> |-<br /> | &lt;code&gt;hydraulic_accuracy&lt;/code&gt; || Relative convergence criterion used by the hydraulic solver || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET hydraulic accuracy<br /> |-<br /> | &lt;code&gt;hydraulic_damping_limit&lt;/code&gt; || Relative accuracy threshold at which hydraulic solution damping/status checks are activated || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET damping limit<br /> |-<br /> | &lt;code&gt;relative_error&lt;/code&gt; || Relative numerical error reported by a solver or conformance check || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || Hydraulic simulation statistics<br /> |-<br /> | &lt;code&gt;flow_balance_ratio&lt;/code&gt; || Ratio of total outflow to total inflow || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET flow-balance reporting<br /> |-<br /> | &lt;code&gt;quality_mass_balance_ratio&lt;/code&gt; || Ratio expressing conservation of transported water-quality mass || dimensionless || &lt;code&gt;1&lt;/code&gt; || ''none'' || EPANET water-quality mass-balance statistic<br /> |}<br /> <br /> === Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |-<br /> | &lt;code&gt;operating_time_percentage&lt;/code&gt; || Fraction of a reporting period during which equipment is operating, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump energy reporting time online<br /> |-<br /> | &lt;code&gt;demand_reduction_percentage&lt;/code&gt; || Reduction in delivered demand relative to requested demand, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Hydraulic simulation statistics<br /> |-<br /> | &lt;code&gt;leakage_loss_percentage&lt;/code&gt; || Leakage loss relative to total system inflow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET leakage-loss statistic<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_100m_pipe_length&lt;/code&gt; || Effective leak area assigned per 100 metres of pipe length || square millimetre per 100 metres (mm²/100 m) || &lt;code&gt;mm2/(100.m)&lt;/code&gt; || &lt;code&gt;mm2_per_100m&lt;/code&gt; || EPANET 2.3 FAVAD leak area; EPANET defines the native value per 100 project length units, so non-metric projects require conversion at the adapter boundary&lt;ref name=&quot;EPANET23&quot;&gt;OWA-EPANET 2.3 release notes https://github.com/OpenWaterAnalytics/EPANET/blob/v2.3/ReleaseNotes2_3.md&lt;/ref&gt;<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre of pressure head (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m_head&lt;/code&gt; || EPANET 2.3 FAVAD leak expansion; non-metric projects require pressure-head conversion at the adapter boundary&lt;ref name=&quot;EPANET23&quot; /&gt;<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input, reaction limiting concentration, quality-source concentration, and simulation results<br /> |-<br /> | &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt; || Chemical mass introduced into or transported through the system per unit time || milligram per minute (mg/min) || &lt;code&gt;mg/min&lt;/code&gt; || &lt;code&gt;mg_per_min&lt;/code&gt; || EPANET mass-booster source strength and reported source mass rate when chemical concentration is canonicalized to mg/L<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting; canonical replacement for backend-dependent power-per-flow-unit values<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Monetary Values and Currencies ==<br /> <br /> Currencies are identifiers for monetary value and are not physical units in the AOWIS measurement system. AOWIS therefore does not encode currencies or currency compounds as UCUM unit identifiers.<br /> <br /> A monetary value MUST identify or reference a currency definition whose identifier is the ISO 4217 alphabetic currency code. The currency definition MAY be managed by the AOWIS Controller or another authoritative subsystem.<br /> <br /> AOWIS MAY support multiple currencies simultaneously. Exchange rates, exchange-rate timestamps, conversion policy, rounding policy, and accounting policy belong to the currency/controller subsystem and MUST NOT be treated as physical unit conversions.<br /> <br /> Where a monetary quantity is normalized by a physical quantity, the physical denominator MUST use the canonical AOWIS physical unit. This yields the following canonical monetary semantics:<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Monetary Quantity Identifier !! Definition !! Currency Representation !! Canonical Physical Denominator !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;energy_price&lt;/code&gt; || Monetary price charged per unit of electrical energy || ISO 4217 currency reference || kilowatt-hour (kWh) || Global and pump-specific energy price<br /> |-<br /> | &lt;code&gt;demand_charge_rate&lt;/code&gt; || Monetary demand charge per unit of peak power || ISO 4217 currency reference || kilowatt (kW) || Global demand charge<br /> |-<br /> | &lt;code&gt;daily_cost_rate&lt;/code&gt; || Monetary cost accumulated or averaged per day || ISO 4217 currency reference || day (d) || Average pump cost, energy cost, demand charge, and total cost reporting<br /> |}<br /> <br /> A monetary value MUST NOT be interpreted without its currency reference. Two monetary values denominated in different currencies MUST NOT be compared, added, or aggregated without an explicit currency conversion performed by the currency/controller subsystem.<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single fixed canonical unit or AOWIS identifier suffix before that context has been resolved.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity. Once resolved to a defined measurement quantity, the value MUST use that quantity's canonical AOWIS unit.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || PRV, PSV, and PBV settings are pressure head; FCV setting is volumetric flow rate; TCV setting is a minor-loss coefficient; PCV setting is valve position; GPV uses a curve reference rather than a numeric physical setting || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Pump setting || Pump speed setting is a pump-speed ratio rather than a flow, head, or percentage || Represent pump settings explicitly as &lt;code&gt;pump_speed_ratio&lt;/code&gt;<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Water-quality solver tolerance || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Bind the tolerance to the selected quality-analysis mode and represent it using that mode's canonical quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Reported source mass rate || Chemical mass flow rate in chemical-quality analysis; other quality-analysis modes must not be mislabeled as chemical mass || Resolve the result through the active quality-analysis mode before assigning &lt;code&gt;chemical_mass_flow_rate&lt;/code&gt;<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use first-order fixed quantities only when the reaction order is exactly first order; otherwise store the coefficient together with reaction order in a discriminated reaction-coefficient structure<br /> |-<br /> | Roughness-correlation reaction parameter || The parameter belongs to the configured wall-reaction correlation model and does not have a universally valid standalone measurement unit || Store it as part of the applicable reaction model rather than assigning a guessed fixed unit<br /> |-<br /> | Emitter coefficient || In the canonical AOWIS emitter equation &lt;code&gt;Q = C H^n&lt;/code&gt;, &lt;code&gt;Q&lt;/code&gt; is volumetric flow rate in m³/h, &lt;code&gt;H&lt;/code&gt; is pressure head in m, and &lt;code&gt;n&lt;/code&gt; is the dimensionless emitter exponent; the dimensional meaning of &lt;code&gt;C&lt;/code&gt; therefore depends on &lt;code&gt;n&lt;/code&gt; || Store the coefficient and exponent together in a dedicated emitter relation. The coefficient MUST NOT claim one fixed standalone UCUM unit for arbitrary non-integer &lt;code&gt;n&lt;/code&gt;<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known; only genuinely generic curves may carry explicit quantity metadata<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity and canonical unit<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration; &lt;code&gt;None&lt;/code&gt; does not define a physical unit || Convert to an explicitly identified geographic, projected, or local coordinate representation before treating the coordinates as physical measurements<br /> |}<br /> <br /> == Boundary Conversion Rules ==<br /> <br /> AOWIS canonical units define the public data contract. Backend-selected unit systems MUST NOT leak into fixed-schema AOWIS measurement fields.<br /> <br /> The EPANET adapter MUST convert EPANET values to and from the canonical AOWIS units whenever EPANET's selected unit system differs from the canonical AOWIS representation.<br /> <br /> This includes, where applicable:<br /> <br /> * volumetric flow rates to and from &lt;code&gt;m3/h&lt;/code&gt;;<br /> * lengths and hydraulic heads to and from &lt;code&gt;m&lt;/code&gt;;<br /> * link diameters to and from &lt;code&gt;mm&lt;/code&gt;;<br /> * tank diameters to and from &lt;code&gt;m&lt;/code&gt;;<br /> * Darcy-Weisbach roughness to and from &lt;code&gt;mm&lt;/code&gt;;<br /> * head-loss gradients to and from &lt;code&gt;m/km&lt;/code&gt;;<br /> * leakage area to and from &lt;code&gt;mm2/(100.m)&lt;/code&gt;;<br /> * leakage expansion to and from &lt;code&gt;mm2/m&lt;/code&gt; of pressure head;<br /> * energy-use reporting to &lt;code&gt;kW.h/m3&lt;/code&gt; where the backend reports power per selected flow unit;<br /> * chemical concentration to &lt;code&gt;mg/L&lt;/code&gt; when chemical-quality support is active;<br /> * chemical mass flow rate to &lt;code&gt;mg/min&lt;/code&gt; when chemical-quality support is active.<br /> <br /> A backend configuration value that selects how the backend displays or interprets units is not itself a substitute for unit information in the AOWIS data contract.<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Fixed-schema fields encode their canonical unit through the normative schema and, where applicable, the AOWIS identifier suffix. Dimensionless fixed-schema fields with UCUM unit &lt;code&gt;1&lt;/code&gt; may omit a unit suffix when their quantity is unambiguous. Generic or dynamically typed physical measurement values carry or resolve to an explicit canonical UCUM unit identifier.<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.<br /> <br /> Monetary fields defined by the model MUST identify or reference an ISO 4217 currency and MUST follow the monetary-value rules on this page.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=672 2026-07-30T14:35:03Z

<p>Samuel: /* Data Model */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier assigned to a measurement quantity is authoritative whenever a unit identifier is represented in serialization or data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> For fixed-schema measurement fields, the measurement quantity and canonical unit MAY be defined normatively by the schema and represented through the field name and its AOWIS identifier suffix. Such fields do not require a separate unit-identifier property.<br /> <br /> When a unit identifier is represented explicitly, it MUST use the canonical UCUM identifier assigned to the measurement quantity. The AOWIS identifier suffix is a technical field-naming convention and is not itself a UCUM unit identifier.<br /> <br /> Generic or dynamically typed measurement values MUST explicitly identify their measurement quantity and canonical UCUM unit and MUST NOT rely solely on a field-name suffix.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Distance Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Dimensionless and Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_pipe_length&lt;/code&gt; || Effective leak area distributed over pipe length || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pipe leakage-area model<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pressure-dependent leak-area expansion<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input and simulation results<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single canonical unit or AOWIS identifier suffix.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || Pressure head, volumetric flow rate, loss coefficient, valve position, or a curve reference, depending on valve type || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use reaction-order-specific quantity fields or a discriminated reaction-coefficient structure<br /> |-<br /> | Emitter coefficient || Volumetric flow rate divided by pressure head raised to the configured emitter exponent || Store the coefficient together with its exponent in a dedicated structure<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration || Convert to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Fixed-schema fields encode their canonical unit through the normative schema and AOWIS identifier suffix; generic or dynamically typed measurement values carry an explicit canonical UCUM unit identifier.<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=671 2026-07-30T14:26:31Z

<p>Samuel: /* Canonical Measurement Quantities and Units */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier assigned to a measurement quantity is authoritative whenever a unit identifier is represented in serialization or data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> For fixed-schema measurement fields, the measurement quantity and canonical unit MAY be defined normatively by the schema and represented through the field name and its AOWIS identifier suffix. Such fields do not require a separate unit-identifier property.<br /> <br /> When a unit identifier is represented explicitly, it MUST use the canonical UCUM identifier assigned to the measurement quantity. The AOWIS identifier suffix is a technical field-naming convention and is not itself a UCUM unit identifier.<br /> <br /> Generic or dynamically typed measurement values MUST explicitly identify their measurement quantity and canonical UCUM unit and MUST NOT rely solely on a field-name suffix.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Distance Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Dimensionless and Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_pipe_length&lt;/code&gt; || Effective leak area distributed over pipe length || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pipe leakage-area model<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pressure-dependent leak-area expansion<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input and simulation results<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single canonical unit or AOWIS identifier suffix.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || Pressure head, volumetric flow rate, loss coefficient, valve position, or a curve reference, depending on valve type || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use reaction-order-specific quantity fields or a discriminated reaction-coefficient structure<br /> |-<br /> | Emitter coefficient || Volumetric flow rate divided by pressure head raised to the configured emitter exponent || Store the coefficient together with its exponent in a dedicated structure<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration || Convert to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=665 2026-07-30T10:43:25Z

<p>Samuel: </p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Distance Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Dimensionless and Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_pipe_length&lt;/code&gt; || Effective leak area distributed over pipe length || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pipe leakage-area model<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pressure-dependent leak-area expansion<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input and simulation results<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single canonical unit or AOWIS identifier suffix.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || Pressure head, volumetric flow rate, loss coefficient, valve position, or a curve reference, depending on valve type || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use reaction-order-specific quantity fields or a discriminated reaction-coefficient structure<br /> |-<br /> | Emitter coefficient || Volumetric flow rate divided by pressure head raised to the configured emitter exponent || Store the coefficient together with its exponent in a dedicated structure<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration || Convert to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=664 2026-07-30T10:42:31Z

<p>Samuel: /* Data Model */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Distance Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Dimensionless and Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_pipe_length&lt;/code&gt; || Effective leak area distributed over pipe length || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pipe leakage-area model<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pressure-dependent leak-area expansion<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input and simulation results<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single canonical unit or AOWIS identifier suffix.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || Pressure head, volumetric flow rate, loss coefficient, valve position, or a curve reference, depending on valve type || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use reaction-order-specific quantity fields or a discriminated reaction-coefficient structure<br /> |-<br /> | Emitter coefficient || Volumetric flow rate divided by pressure head raised to the configured emitter exponent || Store the coefficient together with its exponent in a dedicated structure<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration || Convert to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.<br /> <br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=663 2026-07-28T16:29:12Z

<p>Samuel: /* Data Representation Format */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Distance Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Dimensionless and Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_pipe_length&lt;/code&gt; || Effective leak area distributed over pipe length || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pipe leakage-area model<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pressure-dependent leak-area expansion<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input and simulation results<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single canonical unit or AOWIS identifier suffix.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || Pressure head, volumetric flow rate, loss coefficient, valve position, or a curve reference, depending on valve type || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use reaction-order-specific quantity fields or a discriminated reaction-coefficient structure<br /> |-<br /> | Emitter coefficient || Volumetric flow rate divided by pressure head raised to the configured emitter exponent || Store the coefficient together with its exponent in a dedicated structure<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration || Convert to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=662 2026-07-28T13:58:17Z

<p>Samuel: /* Length and Spatial Quantities */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Distance Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Dimensionless and Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_pipe_length&lt;/code&gt; || Effective leak area distributed over pipe length || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pipe leakage-area model<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pressure-dependent leak-area expansion<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input and simulation results<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single canonical unit or AOWIS identifier suffix.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || Pressure head, volumetric flow rate, loss coefficient, valve position, or a curve reference, depending on valve type || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use reaction-order-specific quantity fields or a discriminated reaction-coefficient structure<br /> |-<br /> | Emitter coefficient || Volumetric flow rate divided by pressure head raised to the configured emitter exponent || Store the coefficient together with its exponent in a dedicated structure<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration || Convert to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=661 2026-07-28T13:57:11Z

<p>Samuel: </p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Spatial Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Dimensionless and Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_pipe_length&lt;/code&gt; || Effective leak area distributed over pipe length || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pipe leakage-area model<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pressure-dependent leak-area expansion<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input and simulation results<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single canonical unit or AOWIS identifier suffix.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || Pressure head, volumetric flow rate, loss coefficient, valve position, or a curve reference, depending on valve type || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use reaction-order-specific quantity fields or a discriminated reaction-coefficient structure<br /> |-<br /> | Emitter coefficient || Volumetric flow rate divided by pressure head raised to the configured emitter exponent || Store the coefficient together with its exponent in a dedicated structure<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration || Convert to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=660 2026-07-28T13:56:32Z

<p>Samuel: /* Canonical Measurement Quantities and Units */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> ```mediawiki<br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Spatial Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Geographic Coordinate Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;latitude&lt;/code&gt; || Angular position north or south of the equator || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 latitude<br /> |-<br /> | &lt;code&gt;longitude&lt;/code&gt; || Angular position east or west of the prime meridian || degree (°) || &lt;code&gt;deg&lt;/code&gt; || &lt;code&gt;deg&lt;/code&gt; || WGS 84 longitude<br /> |-<br /> | &lt;code&gt;projected_easting&lt;/code&gt; || Eastward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate eastings<br /> |-<br /> | &lt;code&gt;projected_northing&lt;/code&gt; || Northward coordinate within a projected coordinate reference system || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || UTM, UPS, and other projected-coordinate northings<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;water_level&lt;/code&gt; || Height of a water surface relative to a defined local reference level || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Initial, minimum, maximum, and simulated tank levels<br /> |-<br /> | &lt;code&gt;head_gain&lt;/code&gt; || Increase in hydraulic head across an energy-adding component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pump head curves and pump simulation results<br /> |-<br /> | &lt;code&gt;head_loss&lt;/code&gt; || Reduction in hydraulic head across a hydraulic component || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Total head loss across pipes, valves, and other energy-dissipating components<br /> |-<br /> | &lt;code&gt;head_loss_gradient&lt;/code&gt; || Hydraulic head loss per unit pipe length || metre per kilometre (m/km) || &lt;code&gt;m/km&lt;/code&gt; || &lt;code&gt;m_per_km&lt;/code&gt; || EPANET pipe head-loss reporting<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Dimensionless and Percentage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;efficiency&lt;/code&gt; || Ratio of useful output to total input, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Pump efficiency values and efficiency curves<br /> |-<br /> | &lt;code&gt;relative_flow&lt;/code&gt; || Flow relative to a defined reference flow, expressed as a percentage || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Valve characteristic curves<br /> |-<br /> | &lt;code&gt;valve_position&lt;/code&gt; || Valve opening position relative to its full operating range || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || Position-control valves and valve characteristic curves<br /> |-<br /> | &lt;code&gt;source_trace_percentage&lt;/code&gt; || Proportion of water originating from a specified source node || percent (%) || &lt;code&gt;%&lt;/code&gt; || &lt;code&gt;percent&lt;/code&gt; || EPANET source-trace analysis<br /> |}<br /> <br /> === Reaction and Leakage Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;first_order_bulk_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance within the bulk fluid || per day (d⁻¹) || &lt;code&gt;/d&lt;/code&gt; || &lt;code&gt;per_d&lt;/code&gt; || Global, pipe-specific, and tank-specific first-order bulk reaction coefficients<br /> |-<br /> | &lt;code&gt;first_order_wall_reaction_coefficient&lt;/code&gt; || First-order reaction-rate coefficient for a substance at a pipe wall || metre per day (m/d) || &lt;code&gt;m/d&lt;/code&gt; || &lt;code&gt;m_per_d&lt;/code&gt; || Global and pipe-specific first-order wall reaction coefficients<br /> |-<br /> | &lt;code&gt;leak_area_per_pipe_length&lt;/code&gt; || Effective leak area distributed over pipe length || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pipe leakage-area model<br /> |-<br /> | &lt;code&gt;leak_area_expansion_per_pressure_head&lt;/code&gt; || Increase in effective leak area per unit pressure head || square millimetre per metre (mm²/m) || &lt;code&gt;mm2/m&lt;/code&gt; || &lt;code&gt;mm2_per_m&lt;/code&gt; || Pressure-dependent leak-area expansion<br /> |}<br /> <br /> === Water Quality Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;chemical_concentration&lt;/code&gt; || Mass concentration of a chemical substance in water || milligram per litre (mg/L) || &lt;code&gt;mg/L&lt;/code&gt; || &lt;code&gt;mg_per_l&lt;/code&gt; || EPANET chemical-quality input and simulation results<br /> |-<br /> | &lt;code&gt;water_age&lt;/code&gt; || Time elapsed since water entered the modelled distribution system || hour (h) || &lt;code&gt;h&lt;/code&gt; || &lt;code&gt;h&lt;/code&gt; || EPANET water-age analysis<br /> |}<br /> <br /> === Power, Energy, and Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt; || Pump power and electrical power<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt; || Pump energy consumption and electrical energy<br /> |-<br /> | &lt;code&gt;energy_intensity&lt;/code&gt; || Energy consumed per unit volume of transported water || kilowatt-hour per cubic metre (kWh/m³) || &lt;code&gt;kW.h/m3&lt;/code&gt; || &lt;code&gt;kw_h_per_m3&lt;/code&gt; || Pump energy-use reporting<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt; || Electrical model<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt; || Electrical model<br /> |}<br /> <br /> == Context-Dependent Measurement Values ==<br /> <br /> A numeric field whose measurement quantity or unit depends on another field, enum, object type, equation, or operating mode MUST NOT be assigned a single canonical unit or AOWIS identifier suffix.<br /> <br /> Such values MUST be represented using quantity-specific fields or a discriminated data structure that identifies the applicable measurement quantity.<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Current Model Concept !! Context-Dependent Meaning !! Required Resolution<br /> |-<br /> | Valve setting || Pressure head, volumetric flow rate, loss coefficient, valve position, or a curve reference, depending on valve type || Replace the generic numeric setting with quantity-specific fields or a discriminated valve-setting structure<br /> |-<br /> | Control action setting || The setting quantity supported by the controlled link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Control trigger level or pressure || Water level or pressure head, depending on the controlled node and control type || Represent water-level and pressure-head triggers separately<br /> |-<br /> | Rule premise value || Demand, hydraulic head, water level, pressure head, volumetric flow rate, power, elapsed time, time of day, fill time, drain time, or another quantity selected by the rule variable || Store the rule variable together with a quantity-specific value representation<br /> |-<br /> | Rule action setting || The setting quantity supported by the target link type || Use the same quantity-specific representation as the target link<br /> |-<br /> | Initial quality and simulation quality || Chemical concentration, water age, or source-trace percentage, depending on the quality-analysis mode || Represent each quality-analysis value using its defined measurement quantity<br /> |-<br /> | Quality-source strength || Chemical concentration or chemical mass flow rate, depending on the quality-source type || Represent source strength using a source-type-specific structure<br /> |-<br /> | Bulk and wall reaction coefficients || The dimensions of the coefficient depend on the configured reaction order || Use reaction-order-specific quantity fields or a discriminated reaction-coefficient structure<br /> |-<br /> | Emitter coefficient || Volumetric flow rate divided by pressure head raised to the configured emitter exponent || Store the coefficient together with its exponent in a dedicated structure<br /> |-<br /> | Generic curve coordinates || Coordinate quantities determined by the curve type || Use a typed curve structure whenever the coordinate quantities are known<br /> |-<br /> | Report thresholds || The measurement quantity of the corresponding report field || Associate each threshold with the report field's defined measurement quantity<br /> |-<br /> | EPANET map and backdrop coordinates || Coordinate units determined by the associated EPANET map or backdrop configuration || Convert to an explicitly identified geographic, projected, or local coordinate representation<br /> |}<br /> ```<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=659 2026-07-28T13:37:23Z

<p>Samuel: </p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for the machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Spatial Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt;<br /> |}<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=658 2026-07-28T13:36:39Z

<p>Samuel: /* Canonical Measurement Quantities and Units */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for their machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and upper case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Spatial Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt;<br /> |}<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=657 2026-07-28T12:39:58Z

<p>Samuel: /* Canonical Measurement Quantities and Units */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for their machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> The canonical UCUM unit identifier is authoritative for serialization and data exchange.<br /> <br /> The AOWIS identifier suffix is an ASCII-safe representation used in field names, property names, database columns, and other technical identifiers. Division is represented by &lt;code&gt;_per_&lt;/code&gt;, multiplication by &lt;code&gt;_&lt;/code&gt;, and letter case is normalized to lower case.<br /> <br /> Each identifier suffix is explicitly defined in the following tables.<br /> <br /> === Length and Spatial Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || &lt;code&gt;m3_per_h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || &lt;code&gt;m_per_s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || &lt;code&gt;kpa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || &lt;code&gt;mpa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Identifier Suffix<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt; || &lt;code&gt;a&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt; || &lt;code&gt;v&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt; || &lt;code&gt;ohm&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt; || &lt;code&gt;kw&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt; || &lt;code&gt;kw_h&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt; || &lt;code&gt;f&lt;/code&gt;<br /> |}<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=656 2026-07-28T12:31:07Z

<p>Samuel: /* Canonical Measurement Quantities and Units */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for their machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> === Length and Spatial Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;length&lt;/code&gt; || Linear spatial extent along an object or path || metre (m) || &lt;code&gt;m&lt;/code&gt; || Pipe and link length<br /> |-<br /> | &lt;code&gt;elevation&lt;/code&gt; || Vertical height relative to an engineering or hydraulic datum || metre (m) || &lt;code&gt;m&lt;/code&gt; || Junction, tank, reservoir, and terrain elevation<br /> |-<br /> | &lt;code&gt;altitude&lt;/code&gt; || Vertical position reported by a geographic positioning source || metre (m) || &lt;code&gt;m&lt;/code&gt; || Geographic altitude; not necessarily suitable as hydraulic elevation<br /> |-<br /> | &lt;code&gt;distance&lt;/code&gt; || Spatial separation between positions || metre (m) || &lt;code&gt;m&lt;/code&gt; || Derived geometric distance<br /> |-<br /> | &lt;code&gt;vertical_offset&lt;/code&gt; || Vertical difference between referenced elevations or heads || metre (m) || &lt;code&gt;m&lt;/code&gt; || Elevation, tank-bottom, and reservoir-head offsets<br /> |-<br /> | &lt;code&gt;link_diameter&lt;/code&gt; || Internal or nominal diameter of a pipe or valve || millimetre (mm) || &lt;code&gt;mm&lt;/code&gt; || EPANET pipe and valve diameter<br /> |-<br /> | &lt;code&gt;tank_diameter&lt;/code&gt; || Internal diameter of a cylindrical storage tank || metre (m) || &lt;code&gt;m&lt;/code&gt; || EPANET tank diameter<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;area&lt;/code&gt; || Two-dimensional spatial extent || square metre (m²) || &lt;code&gt;m2&lt;/code&gt; || Tank cross-sectional area and other geometric areas<br /> |-<br /> | &lt;code&gt;volume&lt;/code&gt; || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || &lt;code&gt;m3&lt;/code&gt; || Tank volume<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;volumetric_flow_rate&lt;/code&gt; || Volume transported per unit time || cubic metre per hour (m³/h) || &lt;code&gt;m3/h&lt;/code&gt; || Demand, link flow, leakage flow, emitter flow, and pump-curve flow<br /> |-<br /> | &lt;code&gt;velocity&lt;/code&gt; || Rate of linear movement || metre per second (m/s) || &lt;code&gt;m/s&lt;/code&gt; || Link flow velocity<br /> |}<br /> <br /> === Hydraulic Head, Pressure, and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;hydraulic_head&lt;/code&gt; || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || Junction, reservoir, and tank hydraulic head<br /> |-<br /> | &lt;code&gt;pressure_head&lt;/code&gt; || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || &lt;code&gt;m&lt;/code&gt; || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings<br /> |-<br /> | &lt;code&gt;pressure&lt;/code&gt; || Normal force per unit area within a fluid system || kilopascal (kPa) || &lt;code&gt;kPa&lt;/code&gt; || Physical pressure measurements, sensors, SCADA data, and external-system exchange<br /> |-<br /> | &lt;code&gt;stress&lt;/code&gt; || Internal force per unit area within a material || megapascal (MPa) || &lt;code&gt;MPa&lt;/code&gt; || Structural and material analysis; not currently represented in the hydraulic model<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping<br /> |-<br /> | &lt;code&gt;elapsed_time&lt;/code&gt; || Time elapsed from a defined simulation or process origin || second (s) || &lt;code&gt;s&lt;/code&gt; || Simulation elapsed time and time-based control triggers<br /> |-<br /> | &lt;code&gt;duration&lt;/code&gt; || Length of a time interval || second (s) || &lt;code&gt;s&lt;/code&gt; || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals<br /> |-<br /> | &lt;code&gt;time_of_day&lt;/code&gt; || Time elapsed since the start of the current day || second (s) || &lt;code&gt;s&lt;/code&gt; || Simulation start time of day and clock-time controls<br /> |}<br /> <br /> === Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier<br /> |-<br /> | &lt;code&gt;electric_current&lt;/code&gt; || Rate of electric charge flow || ampere (A) || &lt;code&gt;A&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;voltage&lt;/code&gt; || Electric potential difference || volt (V) || &lt;code&gt;V&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;electrical_resistance&lt;/code&gt; || Opposition to electric current flow || ohm (Ω) || &lt;code&gt;Ohm&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;power&lt;/code&gt; || Rate of energy transfer || kilowatt (kW) || &lt;code&gt;kW&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;energy&lt;/code&gt; || Work performed or energy transferred || kilowatt-hour (kWh) || &lt;code&gt;kW.h&lt;/code&gt;<br /> |-<br /> | &lt;code&gt;capacitance&lt;/code&gt; || Ability to store electric charge || farad (F) || &lt;code&gt;F&lt;/code&gt;<br /> |}<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=655 2026-07-28T12:21:53Z

<p>Samuel: </p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS uses the canonical SI-based engineering units specified in [[Measurement:Units|Units]]. UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; is the normative syntax and code system for their machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> === Length and Spatial Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | length || Linear spatial extent || m || m || Pipe/link length (SI-normalized EPANET model)<br /> |-<br /> | elevation || Vertical height relative to datum || m || m || Node elevation (SI-normalized EPANET model)<br /> |-<br /> | distance || Spatial separation between points || m || m || Derived geometric quantity<br /> |-<br /> | position_offset || Relative spatial offset magnitude || m || m || Not explicitly represented in EPANET<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | area || Two-dimensional spatial extent || m² || m2 || Not directly used<br /> |-<br /> | volume || Storage volume || m³ || m3 || Tank volume (SI-normalized EPANET model)<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | volumetric_flow_rate || Volume per unit time || m³/s || m3_per_s || Link flow (SI-normalized EPANET model)<br /> |-<br /> | mass_flow_rate || Mass per unit time || kg/s || kg_per_s || Not directly represented (derived)<br /> |}<br /> <br /> === Pressure and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | pressure || Force per unit area in fluid system || Pa || pa || Node pressure (SI-normalized EPANET model)<br /> |-<br /> | stress || Internal material stress || Pa || pa || Not represented<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | time || Simulation or observation time || s || s || Simulation time (EPANET internal time normalized to seconds)<br /> |-<br /> | duration || Time interval length || s || s || Simulation duration / reporting intervals<br /> |}<br /> <br /> === Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit<br /> |-<br /> | current || Rate of electric charge flow || A || a<br /> |-<br /> | voltage || Electric potential difference || V || v<br /> |-<br /> | resistance || Opposition to electric current flow || Ω || ohm<br /> |-<br /> | power || Rate of energy transfer || W || w<br /> |-<br /> | energy || Work or transferred electrical energy || J || j<br /> |-<br /> | capacitance || Ability to store electric charge || F || f<br /> |}<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=654 2026-07-28T12:12:38Z

<p>Samuel: </p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Unit_Identifiers]]<br /> <br /> AOWIS-compliant systems, components, interfaces, and data models MUST use the canonical set of SI-based engineering units defined for measurement quantities in AOWIS.<br /> <br /> SI is the globally accepted standard for scientific and technical measurement and is defined and maintained by the International Bureau of Weights and Measures (BIPM).&lt;ref name=&quot;BIPM-SI&quot;&gt;International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units&lt;/ref&gt;&lt;ref name=&quot;NIST-SI&quot;&gt;NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units&lt;/ref&gt;<br /> <br /> Canonical units are selected individually for each measurement quantity based on the International System of Units (SI), established engineering practice, numerical practicality, and interoperability.<br /> <br /> == Purpose ==<br /> <br /> This specification establishes a single authoritative canonical unit for each measurement quantity represented by AOWIS.<br /> <br /> The use of canonical units reduces implementation complexity, eliminates ambiguity during data exchange, simplifies validation and testing, and improves interoperability between independent AOWIS implementations.<br /> <br /> Each measurement quantity is assigned exactly one canonical unit. Authoritative values within the AOWIS measurement model are represented in that unit.<br /> <br /> Values received in supported alternative units are converted at the applicable system boundary. Values MAY be converted to other units for external systems or user-interface presentation without changing their canonical representation.<br /> <br /> User interfaces MAY display numerical values in supported alternative units for convenience, provided that the displayed unit is clearly indicated. Such presentation does not change the canonical value used by AOWIS.<br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; AOWIS measurement model<br /> : The part of the AOWIS domain model that represents measurement quantities, measurement values, units, precision, timestamps, and measurement provenance.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : The original numerical value and unit representation received from a user, device, file, component, or external system before validation and conversion into the canonical AOWIS representation.<br /> <br /> == Requirements ==<br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing measurement quantities within the AOWIS measurement model MUST be represented using their defined canonical units.<br /> <br /> REQ-MEAS-002: Conversion artifacts, rounding errors, and precision loss introduced by an implementation MUST NOT exceed the documented precision of the measurement.<br /> <br /> REQ-MEAS-003: Interfaces between AOWIS-compliant components and components or systems using non-canonical unit representations MUST perform the required conversion at the applicable boundary. Values entering the AOWIS measurement model MUST be converted to their defined canonical units. Values leaving AOWIS MAY be converted to the representation required by the receiving component or system.<br /> <br /> REQ-MEAS-004: Original source values and their unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from the authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-005: Each distinct measurement quantity in AOWIS MUST be mapped to exactly one canonical unit. Measurement quantities with different meanings MUST have separate identifiers, even when they use the same canonical unit.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> &lt;pre&gt;<br /> REQ-MEAS-UI-001: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.<br /> <br /> REQ-MEAS-UI-002: User interfaces MAY display measurement values in supported non-canonical units for convenience, provided that the displayed unit is clearly indicated.<br /> <br /> REQ-MEAS-UI-003: User interfaces accepting values in non-canonical units MUST convert the entered value to its defined canonical unit before it enters the AOWIS measurement model.<br /> <br /> REQ-MEAS-UI-004: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Notes ==<br /> <br /> External systems MAY use alternative unit systems. Any required conversion between such systems and AOWIS is performed at the system boundary in accordance with REQ-MEAS-003.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=653 2026-07-28T12:08:36Z

<p>Samuel: /* Requirements */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Unit_Identifiers]]<br /> <br /> AOWIS-compliant systems, components, interfaces, and data models MUST use the canonical set of SI-based engineering units defined for measurement quantities in AOWIS.<br /> <br /> SI is the globally accepted standard for scientific and technical measurement and is defined and maintained by the International Bureau of Weights and Measures (BIPM).&lt;ref name=&quot;BIPM-SI&quot;&gt;International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units&lt;/ref&gt;&lt;ref name=&quot;NIST-SI&quot;&gt;NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units&lt;/ref&gt;<br /> <br /> Canonical units are selected individually for each measurement quantity based on the International System of Units (SI), established engineering practice, numerical practicality, and interoperability.<br /> <br /> == Purpose ==<br /> <br /> This specification establishes a single authoritative canonical unit for each measurement quantity represented by AOWIS.<br /> <br /> The use of canonical units reduces implementation complexity, eliminates ambiguity during data exchange, simplifies validation and testing, and improves interoperability between independent AOWIS implementations.<br /> <br /> Each measurement quantity is assigned exactly one canonical unit. Authoritative values within the AOWIS measurement model are represented in that unit.<br /> <br /> Values received in supported alternative units are converted at the applicable system boundary. Values MAY be converted to other units for external systems or user-interface presentation without changing their canonical representation.<br /> <br /> User interfaces MAY display numerical values in supported alternative units for convenience, provided that the displayed unit is clearly indicated. Such presentation does not change the canonical value used by AOWIS.<br /> ```<br /> <br /> <br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; AOWIS measurement model<br /> : The part of the AOWIS domain model that represents measurement quantities, measurement values, units, precision, timestamps, and measurement provenance.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : The original numerical value and unit representation received from a user, device, file, component, or external system before validation and conversion into the canonical AOWIS representation.<br /> <br /> == Requirements ==<br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing physical quantities within the AOWIS measurement model MUST be represented using their defined canonical units.<br /> <br /> REQ-MEAS-002: Implementations MUST NOT introduce conversion artifacts, rounding errors, or precision loss exceeding the documented precision of the measurement.<br /> <br /> REQ-MEAS-003: Interfaces between AOWIS-compliant components and components or systems using non-canonical unit representations MUST perform the required conversion at the applicable boundary. Values entering the AOWIS measurement model MUST be converted to their defined canonical units. Values leaving AOWIS MAY be converted to the representation required by the receiving component or system.<br /> <br /> REQ-MEAS-004: Original source values and their unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from the authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-005: Each distinct measurement quantity in AOWIS MUST be mapped to exactly one canonical unit. Measurement quantities with different meanings MUST have separate identifiers, even when they use the same canonical unit.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> &lt;pre&gt;<br /> REQ-MEAS-UI-001: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.<br /> <br /> REQ-MEAS-UI-002: User interfaces MAY display measurement values in supported non-canonical units for convenience, provided that the displayed unit is clearly indicated.<br /> <br /> REQ-MEAS-UI-003: User interfaces accepting values in non-canonical units MUST convert the entered value to its defined canonical unit before it enters the AOWIS measurement model.<br /> <br /> REQ-MEAS-UI-004: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Notes ==<br /> <br /> External systems MAY use alternative unit systems. Any required conversion between such systems and AOWIS is performed at the system boundary in accordance with REQ-MEAS-003.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=652 2026-07-28T12:02:28Z

<p>Samuel: /* Terminology */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Unit_Identifiers]]<br /> <br /> AOWIS-compliant systems, components, interfaces, and data models MUST use the canonical set of SI-based engineering units defined for measurement quantities in AOWIS.<br /> <br /> SI is the globally accepted standard for scientific and technical measurement and is defined and maintained by the International Bureau of Weights and Measures (BIPM).&lt;ref name=&quot;BIPM-SI&quot;&gt;International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units&lt;/ref&gt;&lt;ref name=&quot;NIST-SI&quot;&gt;NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units&lt;/ref&gt;<br /> <br /> Canonical units are selected individually for each measurement quantity based on the International System of Units (SI), established engineering practice, numerical practicality, and interoperability.<br /> <br /> == Purpose ==<br /> <br /> This specification establishes a single authoritative canonical unit for each measurement quantity represented by AOWIS.<br /> <br /> The use of canonical units reduces implementation complexity, eliminates ambiguity during data exchange, simplifies validation and testing, and improves interoperability between independent AOWIS implementations.<br /> <br /> Each measurement quantity is assigned exactly one canonical unit. Authoritative values within the AOWIS measurement model are represented in that unit.<br /> <br /> Values received in supported alternative units are converted at the applicable system boundary. Values MAY be converted to other units for external systems or user-interface presentation without changing their canonical representation.<br /> <br /> User interfaces MAY display numerical values in supported alternative units for convenience, provided that the displayed unit is clearly indicated. Such presentation does not change the canonical value used by AOWIS.<br /> ```<br /> <br /> <br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; AOWIS measurement model<br /> : The part of the AOWIS domain model that represents measurement quantities, measurement values, units, precision, timestamps, and measurement provenance.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : The original numerical value and unit representation received from a user, device, file, component, or external system before validation and conversion into the canonical AOWIS representation.<br /> <br /> == Requirements ==<br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing physical quantities within the AOWIS measurement model MUST be represented using their defined canonical SI units.<br /> <br /> REQ-MEAS-002: Implementations MUST NOT introduce conversion artifacts, rounding errors, or precision loss exceeding the documented precision of the measurement.<br /> <br /> REQ-MEAS-003: Interfaces between AOWIS-compliant components and components or systems using non-canonical unit representations MUST perform the required conversion at the applicable boundary. Values entering the AOWIS measurement model MUST be converted to their defined canonical SI units. Values leaving AOWIS MAY be converted to the representation required by the receiving component or system.<br /> <br /> REQ-MEAS-004: Original source values and their unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from the authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-005: Each distinct measurement quantity in AOWIS MUST be mapped to exactly one canonical SI unit. Measurement quantities with different meanings MUST have separate identifiers, even when they use the same canonical unit.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> &lt;pre&gt;<br /> REQ-MEAS-UI-000: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.<br /> <br /> REQ-MEAS-UI-001: User interfaces MAY display measurement values in supported non-canonical units for convenience, provided that the displayed unit is clearly indicated.<br /> <br /> REQ-MEAS-UI-002: User interfaces accepting values in non-canonical units MUST convert the entered value to its defined canonical SI unit before it enters the AOWIS measurement model.<br /> <br /> REQ-MEAS-UI-003: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Notes ==<br /> <br /> External systems MAY use alternative unit systems. Any required conversion between such systems and AOWIS is performed at the system boundary in accordance with REQ-MEAS-003.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=651 2026-07-28T12:00:45Z

<p>Samuel: </p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Unit_Identifiers]]<br /> <br /> AOWIS-compliant systems, components, interfaces, and data models MUST use the canonical set of SI-based engineering units defined for measurement quantities in AOWIS.<br /> <br /> SI is the globally accepted standard for scientific and technical measurement and is defined and maintained by the International Bureau of Weights and Measures (BIPM).&lt;ref name=&quot;BIPM-SI&quot;&gt;International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units&lt;/ref&gt;&lt;ref name=&quot;NIST-SI&quot;&gt;NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units&lt;/ref&gt;<br /> <br /> Canonical units are selected individually for each measurement quantity based on the International System of Units (SI), established engineering practice, numerical practicality, and interoperability.<br /> <br /> == Purpose ==<br /> <br /> This specification establishes a single authoritative canonical unit for each measurement quantity represented by AOWIS.<br /> <br /> The use of canonical units reduces implementation complexity, eliminates ambiguity during data exchange, simplifies validation and testing, and improves interoperability between independent AOWIS implementations.<br /> <br /> Each measurement quantity is assigned exactly one canonical unit. Authoritative values within the AOWIS measurement model are represented in that unit.<br /> <br /> Values received in supported alternative units are converted at the applicable system boundary. Values MAY be converted to other units for external systems or user-interface presentation without changing their canonical representation.<br /> <br /> User interfaces MAY display numerical values in supported alternative units for convenience, provided that the displayed unit is clearly indicated. Such presentation does not change the canonical value used by AOWIS.<br /> ```<br /> <br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; AOWIS measurement model<br /> : The part of the AOWIS domain model that represents physical quantities, measurement values, units, precision, timestamps, and measurement provenance.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical SI unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : The original numerical value and unit representation received from a user, device, file, component, or external system before validation and normalization into the canonical AOWIS representation.<br /> <br /> == Requirements ==<br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing physical quantities within the AOWIS measurement model MUST be represented using their defined canonical SI units.<br /> <br /> REQ-MEAS-002: Implementations MUST NOT introduce conversion artifacts, rounding errors, or precision loss exceeding the documented precision of the measurement.<br /> <br /> REQ-MEAS-003: Interfaces between AOWIS-compliant components and components or systems using non-canonical unit representations MUST perform the required conversion at the applicable boundary. Values entering the AOWIS measurement model MUST be converted to their defined canonical SI units. Values leaving AOWIS MAY be converted to the representation required by the receiving component or system.<br /> <br /> REQ-MEAS-004: Original source values and their unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from the authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-005: Each distinct measurement quantity in AOWIS MUST be mapped to exactly one canonical SI unit. Measurement quantities with different meanings MUST have separate identifiers, even when they use the same canonical unit.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> &lt;pre&gt;<br /> REQ-MEAS-UI-000: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.<br /> <br /> REQ-MEAS-UI-001: User interfaces MAY display measurement values in supported non-canonical units for convenience, provided that the displayed unit is clearly indicated.<br /> <br /> REQ-MEAS-UI-002: User interfaces accepting values in non-canonical units MUST convert the entered value to its defined canonical SI unit before it enters the AOWIS measurement model.<br /> <br /> REQ-MEAS-UI-003: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Notes ==<br /> <br /> External systems MAY use alternative unit systems. Any required conversion between such systems and AOWIS is performed at the system boundary in accordance with REQ-MEAS-003.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=650 2026-07-28T11:58:22Z

<p>Samuel: /* Purpose */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Unit_Identifiers]]<br /> <br /> AOWIS-compliant systems, components, interfaces, and data models MUST use a canonical set of SI-based engineering units for measurement quantities represented in the AOWIS measurement model.<br /> <br /> SI is the globally accepted standard for scientific and technical measurement and is defined and maintained by the International Bureau of Weights and Measures (BIPM).&lt;ref name=&quot;BIPM-SI&quot;&gt;International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units&lt;/ref&gt;&lt;ref name=&quot;NIST-SI&quot;&gt;NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units&lt;/ref&gt;<br /> <br /> Canonical units are selected individually for each measurement quantity based on the International System of Units (SI), established engineering practice, numerical practicality, and interoperability.<br /> <br /> == Purpose ==<br /> <br /> This specification establishes a single authoritative unit system for all physical quantities represented by AOWIS.<br /> <br /> The use of a single unit system reduces implementation complexity, eliminates ambiguity during data exchange, simplifies validation and testing, and improves interoperability between independent AOWIS implementations.<br /> <br /> Each measurement quantity is assigned exactly one canonical unit. Authoritative values within the AOWIS measurement model are represented in that unit.<br /> <br /> Values received in other units are converted at the applicable system boundary. Values MAY be converted to other units for external systems or user-interface presentation without changing their authoritative canonical representation.<br /> <br /> User interfaces MAY display numerical values in supported alternative units for convenience, provided that the displayed unit is clearly indicated. Such presentation does not change the authoritative canonical value used by AOWIS.<br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; AOWIS measurement model<br /> : The part of the AOWIS domain model that represents physical quantities, measurement values, units, precision, timestamps, and measurement provenance.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical SI unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : The original numerical value and unit representation received from a user, device, file, component, or external system before validation and normalization into the canonical AOWIS representation.<br /> <br /> == Requirements ==<br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing physical quantities within the AOWIS measurement model MUST be represented using their defined canonical SI units.<br /> <br /> REQ-MEAS-002: Implementations MUST NOT introduce conversion artifacts, rounding errors, or precision loss exceeding the documented precision of the measurement.<br /> <br /> REQ-MEAS-003: Interfaces between AOWIS-compliant components and components or systems using non-canonical unit representations MUST perform the required conversion at the applicable boundary. Values entering the AOWIS measurement model MUST be converted to their defined canonical SI units. Values leaving AOWIS MAY be converted to the representation required by the receiving component or system.<br /> <br /> REQ-MEAS-004: Original source values and their unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from the authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-005: Each distinct measurement quantity in AOWIS MUST be mapped to exactly one canonical SI unit. Measurement quantities with different meanings MUST have separate identifiers, even when they use the same canonical unit.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> &lt;pre&gt;<br /> REQ-MEAS-UI-000: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.<br /> <br /> REQ-MEAS-UI-001: User interfaces MAY display measurement values in supported non-canonical units for convenience, provided that the displayed unit is clearly indicated.<br /> <br /> REQ-MEAS-UI-002: User interfaces accepting values in non-canonical units MUST convert the entered value to its defined canonical SI unit before it enters the AOWIS measurement model.<br /> <br /> REQ-MEAS-UI-003: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Notes ==<br /> <br /> External systems MAY use alternative unit systems. Any required conversion between such systems and AOWIS is performed at the system boundary in accordance with REQ-MEAS-003.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=649 2026-07-28T11:55:44Z

<p>Samuel: </p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Unit_Identifiers]]<br /> <br /> AOWIS-compliant systems, components, interfaces, and data models MUST use a canonical set of SI-based engineering units for measurement quantities represented in the AOWIS measurement model.<br /> <br /> SI is the globally accepted standard for scientific and technical measurement and is defined and maintained by the International Bureau of Weights and Measures (BIPM).&lt;ref name=&quot;BIPM-SI&quot;&gt;International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units&lt;/ref&gt;&lt;ref name=&quot;NIST-SI&quot;&gt;NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units&lt;/ref&gt;<br /> <br /> Canonical units are selected individually for each measurement quantity based on the International System of Units (SI), established engineering practice, numerical practicality, and interoperability.<br /> <br /> == Purpose ==<br /> <br /> This specification establishes a single authoritative unit system for all physical quantities represented by AOWIS.<br /> <br /> The use of a single unit system reduces implementation complexity, eliminates ambiguity during data exchange, simplifies validation and testing, and improves interoperability between independent AOWIS implementations.<br /> <br /> User interfaces MAY display numerical values in supported alternative units for convenience, provided that the displayed unit is clearly indicated. Such presentation does not change the authoritative canonical value used by AOWIS.<br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; AOWIS measurement model<br /> : The part of the AOWIS domain model that represents physical quantities, measurement values, units, precision, timestamps, and measurement provenance.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical SI unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : The original numerical value and unit representation received from a user, device, file, component, or external system before validation and normalization into the canonical AOWIS representation.<br /> <br /> == Requirements ==<br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing physical quantities within the AOWIS measurement model MUST be represented using their defined canonical SI units.<br /> <br /> REQ-MEAS-002: Implementations MUST NOT introduce conversion artifacts, rounding errors, or precision loss exceeding the documented precision of the measurement.<br /> <br /> REQ-MEAS-003: Interfaces between AOWIS-compliant components and components or systems using non-canonical unit representations MUST perform the required conversion at the applicable boundary. Values entering the AOWIS measurement model MUST be converted to their defined canonical SI units. Values leaving AOWIS MAY be converted to the representation required by the receiving component or system.<br /> <br /> REQ-MEAS-004: Original source values and their unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from the authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-005: Each distinct measurement quantity in AOWIS MUST be mapped to exactly one canonical SI unit. Measurement quantities with different meanings MUST have separate identifiers, even when they use the same canonical unit.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> &lt;pre&gt;<br /> REQ-MEAS-UI-000: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.<br /> <br /> REQ-MEAS-UI-001: User interfaces MAY display measurement values in supported non-canonical units for convenience, provided that the displayed unit is clearly indicated.<br /> <br /> REQ-MEAS-UI-002: User interfaces accepting values in non-canonical units MUST convert the entered value to its defined canonical SI unit before it enters the AOWIS measurement model.<br /> <br /> REQ-MEAS-UI-003: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Notes ==<br /> <br /> External systems MAY use alternative unit systems. Any required conversion between such systems and AOWIS is performed at the system boundary in accordance with REQ-MEAS-003.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Units&diff=648 2026-07-28T11:54:05Z

<p>Samuel: </p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Unit_Identifiers]]<br /> <br /> AOWIS-compliant systems, components, interfaces, and data models MUST use a canonical set of SI-based engineering units for measurement quantities represented in the AOWIS measurement model.<br /> <br /> SI is the globally accepted standard for scientific and technical measurement and is defined and maintained by the International Bureau of Weights and Measures (BIPM).&lt;ref name=&quot;BIPM-SI&quot;&gt;International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units&lt;/ref&gt;&lt;ref name=&quot;NIST-SI&quot;&gt;NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units&lt;/ref&gt;<br /> <br /> == Purpose ==<br /> <br /> This specification establishes a single authoritative unit system for all physical quantities represented by AOWIS.<br /> <br /> The use of a single unit system reduces implementation complexity, eliminates ambiguity during data exchange, simplifies validation and testing, and improves interoperability between independent AOWIS implementations.<br /> <br /> User interfaces MAY display numerical values in supported alternative units for convenience, provided that the displayed unit is clearly indicated. Such presentation does not change the authoritative canonical value used by AOWIS.<br /> <br /> == Terminology ==<br /> <br /> ; AOWIS domain model<br /> : The authoritative representation of concepts, entities, relationships, and state managed by AOWIS.<br /> <br /> ; AOWIS measurement model<br /> : The part of the AOWIS domain model that represents physical quantities, measurement values, units, precision, timestamps, and measurement provenance.<br /> <br /> ; Canonical value<br /> : The authoritative numerical representation of a measurement value expressed in the canonical SI unit defined for its measurement quantity.<br /> <br /> ; Source value<br /> : The original numerical value and unit representation received from a user, device, file, component, or external system before validation and normalization into the canonical AOWIS representation.<br /> <br /> == Requirements ==<br /> === General ===<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-001: All authoritative numerical values representing physical quantities within the AOWIS measurement model MUST be represented using their defined canonical SI units.<br /> <br /> REQ-MEAS-002: Implementations MUST NOT introduce conversion artifacts, rounding errors, or precision loss exceeding the documented precision of the measurement.<br /> <br /> REQ-MEAS-003: Interfaces between AOWIS-compliant components and components or systems using non-canonical unit representations MUST perform the required conversion at the applicable boundary. Values entering the AOWIS measurement model MUST be converted to their defined canonical SI units. Values leaving AOWIS MAY be converted to the representation required by the receiving component or system.<br /> <br /> REQ-MEAS-004: Original source values and their unit identifiers MAY be retained as provenance data. Retained source values MUST be clearly distinguished from the authoritative canonical values and MUST NOT be used as authoritative values for computation, comparison, validation, or control logic.<br /> <br /> REQ-MEAS-005: Each distinct measurement quantity in AOWIS MUST be mapped to exactly one canonical SI unit. Measurement quantities with different meanings MUST have separate identifiers, even when they use the same canonical unit.<br /> &lt;/pre&gt;<br /> <br /> === User Interface Specific ===<br /> &lt;pre&gt;<br /> REQ-MEAS-UI-000: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.<br /> <br /> REQ-MEAS-UI-001: User interfaces MAY display measurement values in supported non-canonical units for convenience, provided that the displayed unit is clearly indicated.<br /> <br /> REQ-MEAS-UI-002: User interfaces accepting values in non-canonical units MUST convert the entered value to its defined canonical SI unit before it enters the AOWIS measurement model.<br /> <br /> REQ-MEAS-UI-003: Rounding performed for presentation MUST NOT modify the underlying canonical value.<br /> &lt;/pre&gt;<br /> <br /> == Notes ==<br /> <br /> External systems MAY use alternative unit systems. Any required conversion between such systems and AOWIS is performed at the system boundary in accordance with REQ-MEAS-003.<br /> <br /> == References ==<br /> &lt;references /&gt;</div>

Samuel https://aowis.org/index.php?title=Measurement:Canonical_Units&diff=647 2026-07-28T11:35:05Z

<p>Samuel: /* Data Representation Format */</p> <hr /> <div><br /> * Part of: [[Measurement:Main_Page]]<br /> * Related to: [[Measurement:Units]]<br /> <br /> AOWIS is based on the International System of Units (SI), as specified in [[Measurement:Units|Units]]. Accordingly, AOWIS uses UCUM&lt;ref name=&quot;UCUM&quot;&gt;Unified Code for Units of Measure (UCUM) https://ucum.org&lt;/ref&gt; as the normative syntax and code system for machine-readable unit identifiers.<br /> <br /> AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable SI notation.<br /> <br /> == General Rules ==<br /> <br /> * All unit identifiers MUST conform to UCUM.<br /> * Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> * Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> * Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.<br /> * Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.<br /> <br /> == Requirements ==<br /> <br /> &lt;pre&gt;<br /> REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.<br /> <br /> REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.<br /> <br /> REQ-MEAS-UNI-003: The canonical unit identifier assigned to a measurement quantity MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.<br /> <br /> REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.<br /> &lt;/pre&gt;<br /> <br /> == Canonical Measurement Quantities and Units ==<br /> <br /> === Length and Spatial Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | length || Linear spatial extent || m || m || Pipe/link length (SI-normalized EPANET model)<br /> |-<br /> | elevation || Vertical height relative to datum || m || m || Node elevation (SI-normalized EPANET model)<br /> |-<br /> | distance || Spatial separation between points || m || m || Derived geometric quantity<br /> |-<br /> | position_offset || Relative spatial offset magnitude || m || m || Not explicitly represented in EPANET<br /> |}<br /> <br /> === Area and Volume ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | area || Two-dimensional spatial extent || m² || m2 || Not directly used<br /> |-<br /> | volume || Storage volume || m³ || m3 || Tank volume (SI-normalized EPANET model)<br /> |}<br /> <br /> === Flow and Transport ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | volumetric_flow_rate || Volume per unit time || m³/s || m3_per_s || Link flow (SI-normalized EPANET model)<br /> |-<br /> | mass_flow_rate || Mass per unit time || kg/s || kg_per_s || Not directly represented (derived)<br /> |}<br /> <br /> === Pressure and Stress ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | pressure || Force per unit area in fluid system || Pa || pa || Node pressure (SI-normalized EPANET model)<br /> |-<br /> | stress || Internal material stress || Pa || pa || Not represented<br /> |}<br /> <br /> === Time ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping<br /> |-<br /> | time || Simulation or observation time || s || s || Simulation time (EPANET internal time normalized to seconds)<br /> |-<br /> | duration || Time interval length || s || s || Simulation duration / reporting intervals<br /> |}<br /> <br /> === Electrical Quantities ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> ! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit<br /> |-<br /> | current || Rate of electric charge flow || A || a<br /> |-<br /> | voltage || Electric potential difference || V || v<br /> |-<br /> | resistance || Opposition to electric current flow || Ω || ohm<br /> |-<br /> | power || Rate of energy transfer || W || w<br /> |-<br /> | energy || Work or transferred electrical energy || J || j<br /> |-<br /> | capacitance || Ability to store electric charge || F || f<br /> |}<br /> <br /> == Data Representation Format ==<br /> == Data Model ==<br /> <br /> Concrete AOWIS data structures and field definitions are specified by the [https://github.com/aowis-org/AOWIS-SERVER-MODEL AOWIS Server Model].<br /> <br /> Measurement fields defined by the model MUST use the canonical units specified on this page.</div>

Samuel