Metadata

Note

OntoLearner Metadata will be created automatically at Github under metadata/ directory, and it is available for download after ontolearner > 1.4.0 also at Releases per release.

Hint

The metadata release is fully automated through CI/CD, ensuring it is generated automatically with each PyPI release.

OntoLearner Metadata Exporter Features

• Generates Dublin Core metadata for each ontology in the library

• Creates a top-level Collection resource for OntoLearner

• Supports RDF/XML serialization in a clean, human-readable format

• Uses a custom ontologizer namespace for ontology-specific resources

The OntoLearnerMetadataExporter is a utility class for generating Dublin Core (DCMI) metadata for all ontologies benchmarked in the OntoLearner library. It collects essential metadata, including ontology title and description, creator/authors, license information, format, version, and last updated date, domain and category, and download URL. Additionally, it generates a top-level collection resource that describes the entire OntoLearner benchmarking suite. The output is a pretty-printed RDF/XML file compatible with standard semantic web tools and parsers.

Example RDF structure:

<rdf:RDF
  xmlns:dc="http://purl.org/dc/elements/1.1/"
  xmlns:dcterms="http://purl.org/dc/terms/"
  xmlns:ontologizer="https://ontolearner.readthedocs.io/ontologizer/ontology_modularization.html#"
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">

  <!-- Top-level collection -->
  <ontologizer:Collection rdf:about="https://ontolearner.readthedocs.io/benchmarking/benchmark.html">
    <dc:title>OntoLearner Benchmark Ontologies</dc:title>
    <dc:description>This Dublin Core metadata collection describes ontologies benchmarked in OntoLearner. It includes information such as title, creator, format, license, and version.</dc:description>
    <dc:creator>OntoLearner Team</dc:creator>
    <dcterms:license>MIT License</dcterms:license>
    <dcterms:hasVersion>1.4.0</dcterms:hasVersion>
  </ontologizer:Collection>

  <!-- Individual ontology metadata -->
  <ontologizer:Ontology rdf:about="https://ontolearner.readthedocs.io/benchmarking/medicine/ncit.html">
    <dc:identifier>NCIt</dc:identifier>
    <dcterms:title>NCI Thesaurus (NCIt)</dcterms:title>
    <dcterms:description>NCI Thesaurus (NCIt) is a reference terminology that includes broad coverage of the cancer domain...</dcterms:description>
    <dcterms:format>OWL</dcterms:format>
    <dcterms:date>2023-10-19</dcterms:date>
    <dcterms:license>Creative Commons 4.0</dcterms:license>
    <dcterms:source>https://terminology.tib.eu/ts/ontologies/NCIT</dcterms:source>
    <dcterms:subject>Medicine</dcterms:subject>
    <dcterms:subject>Cancer, Oncology</dcterms:subject>
    <dcterms:hasVersion>24.04e</dcterms:hasVersion>
  </ontologizer:Ontology>

</rdf:RDF>

Properties

The following table summarizes the key Dublin Core metadata properties captured for each ontology in OntoLearner. It provides a quick overview of the ontology’s identifier, title, description, authorship, format, license, domain, and version information, helping users understand and reference the ontologies consistently.

OntoLearner Metadata Properties

Property	Example	Description
dc:identifier	NCIt	Ontology ID
dcterms:title	NCI Thesaurus (NCIt)	Ontology full name
dcterms:description	NCI Thesaurus (NCIt) is a reference terminology that includes broad coverage of the cancer domain…	Detailed ontology description
dcterms:creator	NCI	Creator / author
dcterms:format	OWL	Ontology format
dcterms:date	2023-10-19	Last updated
dcterms:license	Creative Commons 4.0	License information
dcterms:source	https://terminology.tib.eu/ts/ontologies/NCIT	Download or reference URL
dcterms:subject	Medicine	Domain or category
dcterms:hasVersion	24.04e	Ontology version

The following represents the benchmark collection info. The dcterms:hasVersion represents the library version that the metadata was released.

<ontologizer:Collection rdf:about="https://ontolearner.readthedocs.io/benchmarking/benchmark.html">
        <dc:title>OntoLearner Benchmark Ontologies</dc:title>
        <dc:description>This Dublin Core metadata collection describes ontologies benchmarked in OntoLearner. It includes information such as title, creator, format, license, and version.</dc:description>
        <dc:creator>OntoLearner Team</dc:creator>
        <dcterms:license>MIT License</dcterms:license>
        <dcterms:hasVersion>1.4.0</dcterms:hasVersion>
</ontologizer:Collection>

Exporter

OntoLearnerMetadataExporter is included in the OntoLearner library, which you can store the ontology locally.

from ontolearner import OntoLearnerMetadataExporter

# Initialize exporter
exporter = OntoLearnerMetadataExporter()

# Export metadata to RDF/XML
exporter.export("ontolearner-metadata.rdf")

The above code outputs:

• File: ontolearner-metadata.rdf

• Format: Pretty-printed RDF/XML

• Content: metadata for each ontology

The top-level collection describes the entire OntoLearner benchmark, while each ontology entry includes detailed metadata using Dublin Core and DCTERMS properties.

Hint

Namespace Bindings: The exporter uses the following namespaces in the RDF output:

• dc: http://purl.org/dc/elements/1.1/

• dcterms: http://purl.org/dc/terms/

• ontologizer: https://ontolearner.readthedocs.io/ontologizer/ontology_modularization.html#

• rdf: http://www.w3.org/1999/02/22-rdf-syntax-ns#

Note

• The Collection resource always appears first in the RDF/XML output.

• Individual ontologies are serialized as ontologizer:Ontology resources.

• The export() method automatically reads the OntoLearner library version from the VERSION file.

• The RDF/XML output is compatible with standard semantic web tools like Protégé, RDFLib, and Apache Jena.