RUM: Register of Units of Measure
The Register of Units of Measure (RUM) is the canonical example from ISO 19135 Annex D. It demonstrates a Complete Concept Register (CCR) with full governance.
1. General Information
| Register Title | Register of Units of Measure |
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| Register Abbreviation | RUM |
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| Version | 1.0.0 |
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| Date | 2025-01-15 |
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2. Scope and Purpose
| Purpose | To provide a definitive, governed register of units of measure for use in scientific, engineering, and commercial applications. |
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| Scope | - SI base units (meter, kilogram, second, etc.)
- SI derived units (newton, joule, watt, etc.)
- SI prefixes (kilo-, milli-, etc.)
- Non-SI units accepted for use with SI
- Traditional units in common use
|
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| Out of Scope | - Historical/archaic units not in current use
- Domain-specific units (e.g., particle physics)
- Conversion factors (separate register)
|
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| Target Users | Standards bodies, software developers, data integrators, scientific researchers |
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3. Identifier Scheme
| Object Identifier Format | urn:iso:std:iso:19135:rum:{uuid} |
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| Functional Identifier Format | rum:{symbol} (e.g., rum:m for meter) |
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| Assignment Rules | Object identifiers auto-assigned on creation. Functional identifiers assigned by Control Body based on international symbol conventions. |
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| Persistence Policy | Object identifiers guaranteed for the lifetime of the register. Succession plan documented with BIPM as successor organization. |
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4. Content Requirements
| Required Attributes | | Attribute | Type | Description |
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| symbol | String | Unit symbol (e.g., "m", "kg") | | name | String | Full unit name (e.g., "meter") | | definition | String | Formal definition | | unitType | Enumeration | base, derived, prefix, traditional |
|
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| Optional Attributes | | Attribute | Type | Description |
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| quantity | String | Physical quantity (e.g., "length") | | siBaseUnit | Boolean | Is this an SI base unit? | | derivation | String | For derived units, the derivation formula | | status | Enumeration | current, deprecated, historical |
|
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5. Versioning
| Versioning Scheme | Semantic (MAJOR.MINOR.PATCH) |
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| Substantive Change Criteria | - Change to symbol or name
- Change to definition that alters meaning
- Change to derivation formula
- Change to unitType classification
|
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6. Governance Model
| Register Owner | ISO/TC 211 Secretariat |
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| Register Manager | ISO Central Secretariat, Registry Services |
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| Control Body | ISO/TC 211 WG 6 (Image, grid and coverage data) |
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| Proposal Process | - Proposer submits via ISO portal with justification
- Manager validates completeness within 5 working days
- Control Body reviews at monthly meeting
- Decision communicated within 10 working days of meeting
|
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| Approval Criteria | - Unit is in recognized use
- Definition is clear and unambiguous
- Symbol doesn't conflict with existing units
- Proposal includes supporting references
|
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| Appeal Process | Appeals to ISO/TC 211 Chair within 30 days. Chair's decision final or may escalate to ISO Technical Management Board. |
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7. Commitments
| Commitment | Level | Description |
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| Access - Metadata | High | Publicly accessible via API and web interface |
| Access - Content | High | Full content publicly accessible |
| Access - Historic | High | All versions accessible via API |
| Persistence - Identifier | High | Indefinite; succession agreement with BIPM |
| Persistence - Content | High | All versions preserved permanently |
| Persistence - Historic | High | Complete change records preserved |
| Transparency | High | Full provenance, proposals, and decisions visible |
8. Conformance Claims
| Register Type | Complete Concept Register (CCR) |
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| Capabilities | - Content management
- Concept plane modeling
- Full governance
- Complete commitments
|
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Sample Items
Meter
{
"identifier": "urn:iso:std:iso:19135:rum:a1b2c3d4",
"functionalId": "rum:m",
"symbol": "m",
"name": "meter",
"definition": "The metre, symbol m, is the SI unit of length...",
"unitType": "base",
"quantity": "length",
"siBaseUnit": true,
"status": {
"valid": true,
"published": true,
"superseded": false
},
"dates": {
"added": "1960-10-14",
"modified": "1983-10-20"
},
"versions": [
{
"version": "1.0.0",
"date": "1960-10-14",
"definition": "The metre is the length equal to 1,650,763.73 wavelengths..."
},
{
"version": "2.0.0",
"date": "1983-10-20",
"definition": "The metre is the length of the path travelled by light..."
}
]
}
