Measurement:Units - Revision history

Samuel at 11:11, 19 August 2026

2026-08-19T11:11:55Z

@@ Line 8: / Line 8: @@
 == Purpose ==
-This specification defines how measurement quantities, values, units, conversions, and measurement-related numeric data are represented and handled by AOWIS.
+This specification defines the AOWIS unit system for measurement quantities, including canonical representation, unit identifiers, boundary conversion, and the resolution of context-dependent units.
 A single canonical representation:
@@ Line 72: / Line 72: @@
 REQ-MEAS-011: Conversion artifacts, rounding errors, and precision loss introduced by an implementation MUST NOT exceed the documented precision of the measurement.
-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.
+REQ-MEAS-012: A retained non-canonical source representation MUST be clearly distinguished from the authoritative canonical value.
 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.
@@ Line 127: / Line 127: @@
 |-
 | PRV setting <code>30 m</code> || Setting resolved to pressure head
 |}

Samuel at 17:18, 18 August 2026

2026-08-18T17:18:50Z

@@ Line 127: / Line 127: @@
 |-
 | PRV setting <code>30 m</code> || Setting resolved to pressure head
 |}

Samuel at 15:20, 18 August 2026

2026-08-18T15:20:18Z

Show changes

Samuel at 12:12, 28 July 2026

2026-07-28T12:12:38Z

← Older revision		Revision as of 12:12, 28 July 2026
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	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.		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.
	~~```~~



	== Terminology ==		== Terminology ==
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	<pre>		<pre>
	REQ-MEAS-001: All authoritative numerical values representing ~~physical~~ quantities within the AOWIS measurement model MUST be represented using their defined canonical units.		REQ-MEAS-001: All authoritative numerical values representing measurement quantities within the AOWIS measurement model MUST be represented using their defined canonical units.

	REQ-MEAS-002: ~~Implementations MUST NOT introduce conversion~~ artifacts, rounding errors, or precision loss ~~exceeding~~ the documented precision of the measurement.		REQ-MEAS-002: Conversion artifacts, rounding errors, and precision loss introduced by an implementation MUST NOT exceed the documented precision of the measurement.

	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.		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.

Samuel: /* Requirements */

2026-07-28T12:08:36Z

Requirements

Samuel: /* Terminology */

2026-07-28T12:02:28Z

Terminology

← Older revision		Revision as of 12:02, 28 July 2026
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	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.		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.
	```		```



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	; AOWIS measurement model		; AOWIS measurement model
	: The part of the AOWIS domain model that represents ~~physical~~ quantities, measurement values, units, precision, timestamps, and measurement provenance.		: The part of the AOWIS domain model that represents measurement quantities, measurement values, units, precision, timestamps, and measurement provenance.

	; Canonical value		; Canonical value
	: The authoritative numerical representation of a measurement value expressed in the canonical SI unit defined for its measurement quantity.		: The authoritative numerical representation of a measurement value expressed in the canonical unit defined for its measurement quantity.

	; Source value		; Source value
	: 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.		: 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.

	== Requirements ==		== Requirements ==

Samuel at 12:00, 28 July 2026

2026-07-28T12:00:45Z

← Older revision		Revision as of 12:00, 28 July 2026
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	* Related to: [[Measurement:Unit_Identifiers]]		* Related to: [[Measurement:Unit_Identifiers]]

	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~~.		AOWIS-compliant systems, components, interfaces, and data models MUST use the canonical set of SI-based engineering units defined for measurement quantities in AOWIS.

	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).<ref name="BIPM-SI">International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units</ref><ref name="NIST-SI">NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units</ref>		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).<ref name="BIPM-SI">International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units</ref><ref name="NIST-SI">NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units</ref>
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	== Purpose ==		== Purpose ==

	This specification establishes a single authoritative unit ~~system~~ for ~~all physical quantities~~ represented by AOWIS.		This specification establishes a single authoritative canonical unit for each measurement quantity represented by AOWIS.

	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.		The use of canonical units reduces implementation complexity, eliminates ambiguity during data exchange, simplifies validation and testing, and improves interoperability between independent AOWIS implementations.

	Each measurement quantity is assigned exactly one canonical unit. Authoritative values within the AOWIS measurement model are represented in that unit.		Each measurement quantity is assigned exactly one canonical unit. Authoritative values within the AOWIS measurement model are represented in that unit.

	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.		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.

			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.
			```

	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.

	== Terminology ==		== Terminology ==

Samuel: /* Purpose */

2026-07-28T11:58:22Z

Purpose

← Older revision		Revision as of 11:58, 28 July 2026
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	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.		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.

			Each measurement quantity is assigned exactly one canonical unit. Authoritative values within the AOWIS measurement model are represented in that unit.

			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.

	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.		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.

Samuel at 11:55, 28 July 2026

2026-07-28T11:55:44Z

← Older revision		Revision as of 11:55, 28 July 2026
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	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).<ref name="BIPM-SI">International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units</ref><ref name="NIST-SI">NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units</ref>		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).<ref name="BIPM-SI">International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units</ref><ref name="NIST-SI">NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units</ref>

			Canonical units are selected individually for each measurement quantity based on the International System of Units (SI), established engineering practice, numerical practicality, and interoperability.

	== Purpose ==		== Purpose ==

Samuel at 11:54, 28 July 2026

2026-07-28T11:54:05Z

← Older revision		Revision as of 11:54, 28 July 2026
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	* Related to: [[Measurement:Unit_Identifiers]]		* Related to: [[Measurement:Unit_Identifiers]]

	AOWIS-compliant systems, components, interfaces, and data models MUST use ~~the International System~~ of ~~Units (~~SI~~) as the canonical unit system~~ for ~~physical~~ quantities represented in the AOWIS measurement model.~~<ref name="NIST-SI">NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units</ref>~~		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.

	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).<ref name="BIPM-SI">International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units</ref>		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).<ref name="BIPM-SI">International Bureau of Weights and Measures (BIPM) — International System of Units (SI) https://www.bipm.org/en/measurement-units/si-base-units</ref><ref name="NIST-SI">NIST — The International System of Units (SI) https://www.nist.gov/pml/owm/metric-si/si-units</ref>

	== Purpose ==		== Purpose ==

← Older revision		Revision as of 12:08, 28 July 2026
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	<pre>		<pre>
	REQ-MEAS-001: All authoritative numerical values representing physical quantities within the AOWIS measurement model MUST be represented using their defined canonical SI units.		REQ-MEAS-001: All authoritative numerical values representing physical quantities within the AOWIS measurement model MUST be represented using their defined canonical units.

	REQ-MEAS-002: Implementations MUST NOT introduce conversion artifacts, rounding errors, or precision loss exceeding the documented precision of the measurement.		REQ-MEAS-002: Implementations MUST NOT introduce conversion artifacts, rounding errors, or precision loss exceeding the documented precision of the measurement.

	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.		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.

	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.		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.

	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.		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.
	</pre>		</pre>

	=== User Interface Specific ===		=== User Interface Specific ===
	<pre>		<pre>
	REQ-MEAS-UI-~~000~~: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.		REQ-MEAS-UI-001: User interfaces MUST clearly indicate the unit associated with every displayed or entered numerical value representing a physical quantity.

	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.		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.

	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.		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.

	REQ-MEAS-UI-~~003~~: Rounding performed for presentation MUST NOT modify the underlying canonical value.		REQ-MEAS-UI-004: Rounding performed for presentation MUST NOT modify the underlying canonical value.
	</pre>		</pre>