C.2 QUDT syntax reference
| Type | Ontology |
| Coverage | Limited / around 1750 Units originating from 10 systems of units for 880 quantity kinds |
| Hosted by | public charity non-profit organization |
| Homepage |
The QUDT ontology includes
physical constants, quantity kinds, units, unit systems, prefixes and dimension vectors
a semantic description of the named entries including the relation to other entries
translations to other standards of unit description
QUDT is modelled in OWL (Web Ontology Language). Other descriptions and interfaces are available like RDF/XML, TURTLE, JSON or SPARQL.
QUDT not only focuses on defining models and a publicly available vocabulary to express quantities and units but also wants to offer a translation between existing standards doing the same. Therefore, the ontology also names UCUM, UNECE, IEC 61360 and LaTeX codes for the entries.
QUDT originated from a NASA project trying to define a semantic specification for units of measure, quantity kind and dimensions used in science and engineering. Today it is governed by a board of directors from different research institutes and the industry.
Quantity examples:
| QUDT code | Symbol | Name |
|---|---|---|
| quantitykind:Length | l | length |
| quantitykind:LinearThermalExpansion | m/K | linear thermal expansion |
Unit examples:
| QUDT code | Symbol | Name |
|---|---|---|
| unit:M | m | metre |
| unit:CentiM | cm | centimetre |
| unit:MI_N | n mile | nautical mile |
| unit:ANGSTROM | Å | angstrom |
| unit:MicroM-PER-K | µm/K | micrometre per kelvin |
| unit:FATH | fath | fathom |