Jump to content

Measurement:Unit Identifiers: Difference between revisions

From AOWIS
← Older editNewer edit →

Samuel (talk | contribs)

6 user groups
645 edits
VisualWikitext
mNo edit summary
Line 34: Line 34:


{| class="wikitable"
{| class="wikitable"
! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping
! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping
|-
|-
| length || Linear spatial extent || m || m || Pipe/link length (SI-normalized EPANET model)
| <code>length</code> || Linear spatial extent along an object or path || metre (m) || <code>m</code> || Pipe and link length
|-
|-
| elevation || Vertical height relative to datum || m || m || Node elevation (SI-normalized EPANET model)
| <code>elevation</code> || Vertical height relative to an engineering or hydraulic datum || metre (m) || <code>m</code> || Junction, tank, reservoir, and terrain elevation
|-
|-
| distance || Spatial separation between points || m || m || Derived geometric quantity
| <code>altitude</code> || Vertical position reported by a geographic positioning source || metre (m) || <code>m</code> || Geographic altitude; not necessarily suitable as hydraulic elevation
|-
|-
| position_offset || Relative spatial offset magnitude || m || m || Not explicitly represented in EPANET
| <code>distance</code> || Spatial separation between positions || metre (m) || <code>m</code> || Derived geometric distance
|-
| <code>vertical_offset</code> || Vertical difference between referenced elevations or heads || metre (m) || <code>m</code> || Elevation, tank-bottom, and reservoir-head offsets
|-
| <code>link_diameter</code> || Internal or nominal diameter of a pipe or valve || millimetre (mm) || <code>mm</code> || EPANET pipe and valve diameter
|-
| <code>tank_diameter</code> || Internal diameter of a cylindrical storage tank || metre (m) || <code>m</code> || EPANET tank diameter
|}
|}


Line 48: Line 54:


{| class="wikitable"
{| class="wikitable"
! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping
! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping
|-
|-
| area || Two-dimensional spatial extent || m² || m2 || Not directly used
| <code>area</code> || Two-dimensional spatial extent || square metre (m²) || <code>m2</code> || Tank cross-sectional area and other geometric areas
|-
|-
| volume || Storage volume || m³ || m3 || Tank volume (SI-normalized EPANET model)
| <code>volume</code> || Three-dimensional spatial extent or storage capacity || cubic metre (m³) || <code>m3</code> || Tank volume
|}
|}


Line 58: Line 64:


{| class="wikitable"
{| class="wikitable"
! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping
! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping
|-
|-
| volumetric_flow_rate || Volume per unit time || m³/s || m3_per_s || Link flow (SI-normalized EPANET model)
| <code>volumetric_flow_rate</code> || Volume transported per unit time || cubic metre per hour (m³/h) || <code>m3/h</code> || Demand, link flow, leakage flow, emitter flow, and pump-curve flow
|-
|-
| mass_flow_rate || Mass per unit time || kg/s || kg_per_s || Not directly represented (derived)
| <code>velocity</code> || Rate of linear movement || metre per second (m/s) || <code>m/s</code> || Link flow velocity
|}
|}


=== Pressure and Stress ===
=== Hydraulic Head, Pressure, and Stress ===


{| class="wikitable"
{| class="wikitable"
! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping
! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping
|-
| <code>hydraulic_head</code> || Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height || metre (m) || <code>m</code> || Junction, reservoir, and tank hydraulic head
|-
|-
| pressure || Force per unit area in fluid system || Pa || pa || Node pressure (SI-normalized EPANET model)
| <code>pressure_head</code> || Fluid pressure expressed as an equivalent fluid-column height || metre (m) || <code>m</code> || EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings
|-
|-
| stress || Internal material stress || Pa || pa || Not represented
| <code>pressure</code> || Normal force per unit area within a fluid system || kilopascal (kPa) || <code>kPa</code> || Physical pressure measurements, sensors, SCADA data, and external-system exchange
|-
| <code>stress</code> || Internal force per unit area within a material || megapascal (MPa) || <code>MPa</code> || Structural and material analysis; not currently represented in the hydraulic model
|}
|}


Line 78: Line 88:


{| class="wikitable"
{| class="wikitable"
! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit !! EPANET Mapping
! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier !! AOWIS Model / EPANET Mapping
|-
| <code>elapsed_time</code> || Time elapsed from a defined simulation or process origin || second (s) || <code>s</code> || Simulation elapsed time and time-based control triggers
|-
|-
| time || Simulation or observation time || s || s || Simulation time (EPANET internal time normalized to seconds)
| <code>duration</code> || Length of a time interval || second (s) || <code>s</code> || Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals
|-
|-
| duration || Time interval length || s || s || Simulation duration / reporting intervals
| <code>time_of_day</code> || Time elapsed since the start of the current day || second (s) || <code>s</code> || Simulation start time of day and clock-time controls
|}
|}


Line 88: Line 100:


{| class="wikitable"
{| class="wikitable"
! Quantity / Name !! Definition !! Canonical Unit (SI symbol) !! Serialized Unit
! Measurement Quantity Identifier !! Definition !! Canonical Unit !! Canonical UCUM Unit Identifier
|-
|-
| current || Rate of electric charge flow || A || a
| <code>electric_current</code> || Rate of electric charge flow || ampere (A) || <code>A</code>
|-
|-
| voltage || Electric potential difference || V || v
| <code>voltage</code> || Electric potential difference || volt (V) || <code>V</code>
|-
|-
| resistance || Opposition to electric current flow || Ω || ohm
| <code>electrical_resistance</code> || Opposition to electric current flow || ohm (Ω) || <code>Ohm</code>
|-
|-
| power || Rate of energy transfer || W || w
| <code>power</code> || Rate of energy transfer || kilowatt (kW) || <code>kW</code>
|-
|-
| energy || Work or transferred electrical energy || J || j
| <code>energy</code> || Work performed or energy transferred || kilowatt-hour (kWh) || <code>kW.h</code>
|-
|-
| capacitance || Ability to store electric charge || F || f
| <code>capacitance</code> || Ability to store electric charge || farad (F) || <code>F</code>
|}
|}


Revision as of 12:31, 28 July 2026

AOWIS uses the canonical SI-based engineering units specified in Units. UCUM[1] is the normative syntax and code system for their machine-readable unit identifiers.

AOWIS defines a canonical set of UCUM unit identifiers used across all system interfaces, storage formats, APIs, and inter-system data exchanges.

Unit identifiers are machine-readable tokens and are not intended to represent typographic or human-readable unit notation.

General Rules

  • All unit identifiers MUST conform to UCUM.
  • Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.
  • Canonical unit identifiers MUST be used consistently across all AOWIS-compliant systems, interfaces, storage formats, APIs, and inter-system data exchanges.
  • Canonical unit identifiers MUST be interpreted independently of locale, display format, implementation, and system context.
  • Canonical unit identifiers MUST remain stable across AOWIS-compliant systems and data formats.

Requirements

REQ-MEAS-UNI-001: All unit identifiers MUST conform to UCUM.

REQ-MEAS-UNI-002: Each measurement quantity MUST be assigned exactly one UCUM unit identifier as its canonical unit identifier.

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.

REQ-MEAS-UNI-004: The measurement quantity identifier defines what is measured, while the unit identifier defines the unit in which it is expressed.

Canonical Measurement Quantities and Units

Length and Spatial Quantities

Measurement Quantity Identifier Definition Canonical Unit Canonical UCUM Unit Identifier AOWIS Model / EPANET Mapping
length Linear spatial extent along an object or path metre (m) m Pipe and link length
elevation Vertical height relative to an engineering or hydraulic datum metre (m) m Junction, tank, reservoir, and terrain elevation
altitude Vertical position reported by a geographic positioning source metre (m) m Geographic altitude; not necessarily suitable as hydraulic elevation
distance Spatial separation between positions metre (m) m Derived geometric distance
vertical_offset Vertical difference between referenced elevations or heads metre (m) m Elevation, tank-bottom, and reservoir-head offsets
link_diameter Internal or nominal diameter of a pipe or valve millimetre (mm) mm EPANET pipe and valve diameter
tank_diameter Internal diameter of a cylindrical storage tank metre (m) m EPANET tank diameter

Area and Volume

Measurement Quantity Identifier Definition Canonical Unit Canonical UCUM Unit Identifier AOWIS Model / EPANET Mapping
area Two-dimensional spatial extent square metre (m²) m2 Tank cross-sectional area and other geometric areas
volume Three-dimensional spatial extent or storage capacity cubic metre (m³) m3 Tank volume

Flow and Transport

Measurement Quantity Identifier Definition Canonical Unit Canonical UCUM Unit Identifier AOWIS Model / EPANET Mapping
volumetric_flow_rate Volume transported per unit time cubic metre per hour (m³/h) m3/h Demand, link flow, leakage flow, emitter flow, and pump-curve flow
velocity Rate of linear movement metre per second (m/s) m/s Link flow velocity

Hydraulic Head, Pressure, and Stress

Measurement Quantity Identifier Definition Canonical Unit Canonical UCUM Unit Identifier AOWIS Model / EPANET Mapping
hydraulic_head Total mechanical energy per unit weight of fluid expressed as an equivalent fluid-column height metre (m) m Junction, reservoir, and tank hydraulic head
pressure_head Fluid pressure expressed as an equivalent fluid-column height metre (m) m EPANET node pressure, pressure-driven demand thresholds, and pressure-control valve settings
pressure Normal force per unit area within a fluid system kilopascal (kPa) kPa Physical pressure measurements, sensors, SCADA data, and external-system exchange
stress Internal force per unit area within a material megapascal (MPa) MPa Structural and material analysis; not currently represented in the hydraulic model

Time

Measurement Quantity Identifier Definition Canonical Unit Canonical UCUM Unit Identifier AOWIS Model / EPANET Mapping
elapsed_time Time elapsed from a defined simulation or process origin second (s) s Simulation elapsed time and time-based control triggers
duration Length of a time interval second (s) s Simulation duration, hydraulic timesteps, quality timesteps, reporting intervals, and rule intervals
time_of_day Time elapsed since the start of the current day second (s) s Simulation start time of day and clock-time controls

Electrical Quantities

Measurement Quantity Identifier Definition Canonical Unit Canonical UCUM Unit Identifier
electric_current Rate of electric charge flow ampere (A) A
voltage Electric potential difference volt (V) V
electrical_resistance Opposition to electric current flow ohm (Ω) Ohm
power Rate of energy transfer kilowatt (kW) kW
energy Work performed or energy transferred kilowatt-hour (kWh) kW.h
capacitance Ability to store electric charge farad (F) F

Data Representation Format

Data Model

Concrete AOWIS data structures and field definitions are specified by the AOWIS Server Model.

Measurement fields defined by the model MUST use the canonical units specified on this page.

  1. ↑ Unified Code for Units of Measure (UCUM) https://ucum.org
Retrieved from "https://aowis.org/index.php?title=Measurement:Unit_Identifiers&oldid=656"