metaphacts schema.org Ontology Transformation Script

Requirements

In order to execute the transformation script locally, Python version 3.6 and above is required. Please also note that when you execute the script for the first time, it may fail if requirements are not satisfied (see section How to use ).

Description

We have created a transformation script for the schema.org Ontology that creates an OWL ontology and the corresponding SHACL shapes. The transformation script builds upon the existing schema.org python scripts.

Our build script downloads the schema.org repository from git (https://github.com/schemaorg/schemaorg) and checks out the latest stable release (currently tags/v22.0-release).

Heuristics

schema.org typically uses rdf:Property and additional domainIncludes or rangeIncludes to define attribute and relations for classes. This can result in mixed property ranges (e.g., schema:URL, schema:Text, schema:Thing)

Our transformation script uses a heuristic to deal with such cases. In this heuristic, we remove all datatype. In most cases the datatype is a string therefore the assignment to object properties with their ranges provides more semantic expressivity.

Additionally, we provide a configuration file config.json This configuration file provides the means to overwrite the range for specified properties.

"propertyMapper": {
    "https://schema.org/image":"http://www.w3.org/2001/XMLSchema#anyURI",
    "https://schema.org/logo":"http://www.w3.org/2001/XMLSchema#anyURI",
    "https://schema.org/photo":"http://www.w3.org/2001/XMLSchema#anyURI",
    "https://schema.org/jobTitle":"http://www.w3.org/2001/XMLSchema#string"
  },

The propertyMapper is an object that takes a list of tuples. The first element it the schema property we want to overwrite. The second element represents the range. Please note that all other ranges will be removed.

Filtering

The configuration file provides additional means to filter only related classes and properties for specific use cases. We provide an example configuration file for the resourcehub use case resourcehub-example-config.json.

Please note that the transformation script takes the content of the config.json file for mappings and filtering. Additionally, these filtering mechanisms do not provide any reasoning on subclasses or the inherited properties form superclasses.

Shapes and Restrictions

We exclude rdfs:domain and rdfs:range form the generation. Instead we provide SHACL shapes for the individual classes and their attributes and relations.

Generated Ontologies

The transformation script provides three output files which are stored in the ontologies folder.

• schema-org.ttl The full schema.org model including OWL declarations (for classes, relations and attributes) and SHACL Shapes.
• schema-org-owl.ttl Only OWL declarations of the schema.org model
• schema-org-shacl-shapes.ttl Only SHACL shapes of the schema.org model

How to use

• ./build.sh

  • Downloads the schema.org repository and switch to the lates stable release version based on the branch tag (currently tags/v15.0-release)
  • Please note: you might need to install additional python modules to execute the the transformation script. The schemaorg/software has the requirements.txt file. Please switch to this folder and execute pip3 install -r requirements.txt if additional packages are required.

• run ./clear.sh to remove the schemaorg git repository from the file system