Skip to content

Ontology File Formats

General

The registry for ITS ontologies (RITSO) intends to capture ontologies for ITS documented in widely accepted file formats that can be managed with a modern version control system and that can easily be translated into a website, including diagrams showing key references. The following technologies have been selected to achieve this management:

  • GitHub: for version control
  • Web Ontology Language (OWL): for specifying the semantics of the ontology
  • W3C Turtle (*.ttl) file format: for formally specifying OWL content
  • The python scripts developed by this registry effort: to convert the *.ttl files into a more human-friendly source files
  • GraphViz: to convert the text description of graphics into actual graphics
  • Material for MkDocs: to convert the source files into a website

Namespaces

This page refers to the following namespaces:

  • dcterms: http://purl.org/dc/terms/
  • owl: http://www.w3.org/2002/07/owl#
  • protoge: http://protege.stanford.edu/ontologies/metadata#
  • skos: http://www.w3.org/2004/02/skos/core#

This minimizes imports to just four namespaces (RDFS and OWL are typically already imported in any OWL ontology, so effectively adding only DCTERMS and SKOS).

The ITS Ontology Registry recommends using the following annotations when describing ontological elements.

Annotation Rationale and Usage Notes
skos:definition Normative definition of the entity. Use no more than once per language.
dcterms:source Cite origin or reference; can use multiples.
skos:note Informative details as needed; can use multiples.
skos:example Illustrative example; can use multiples.
dcterms:license Identifies legal usage terms; used in ontology header.
dcterms:created For creation date; used for ontology IRI.
dcterms:modified Identifies the date of an update date; pair with repeatable skos:changeNote for descriptions.
skos:changeNote Provides a description of the update date; pair with dcterms:modified
dcterms:replaces Identifies a historic ontological element that is replaced by a new ontological element; repeatable if needed.
dcterms:isReplacedBy Identifies a new element that replaces a historic element; repeatable if needed. Inverse of the above
owl:deprecated Boolean (true for deprecated/obsolete)
:pii Boolean (true for personally identifiable information)
protoge:abstract Indicates that the class is not intended for direct instantiation.