DCAT in (to) LinkML

An experiment to create a linkML model that matches dcat 2.2 and dcat 3 from dcat specification in rdf.

DCAT as Owl ontology in RDF:

• DCAT, Version 2:
  • Specification, v2.2: https://www.w3.org/ns/dcat#
  • Turtle file url: https://www.w3.org/ns/dcat2.ttl
• DCAT, Version 3: https://www.w3.org/standards/history/vocab-dcat-3/ (RDF serializations are in DXWG GitHub repository)
  • Latest version: https://www.w3.org/TR/vocab-dcat-3/
  • Turtle file url: https://raw.githubusercontent.com/w3c/dxwg/gh-pages/dcat/rdf/dcat3.ttl (Proposed recommendation 2024-06-13, but file is last changed 2023-02-02)

Here we try a conversion with schema-automator from the linkML team.

First, create a virtual environment and install schema-automator.

py -3.12 -m venv .venv
.venv/scripts/activate
pip install schema-automator notebook

The exact versions of all packages used are documented in requirements_frozen.txt (created by pip freeze > requirements_frozen.txt).

With schema-automator it is possible to import from a schema-style OWL ontology. This must be in functional syntax which can be created with robot ahead of time:

robot convert -i dcat-source-rdf/dcat2.ttl -o dcat-source-rdf/dcat2.ofn

schemauto import-owl dcat-source-rdf/dcat2.ofn -o linkML/dcat2.yaml

See linkml/README.txt for details of the conversion process. The obtained LinkML models (in yaml) are in linkml/.

This is only a first experiment without any validation or polishing.

It demonstrates the outcome of using standard commands/tools without tweaking options.