DCAT-AP Plus Links to Use-case Specific Context (DCAT-AP+)

DCAT-AP+ is a LinkML-based extension of the DCAT Application Profile 3.0 that adds a provenance layer for describing how a dataset was generated and what it is about, using the Starting Point Terms of PROV-O, the QUDT ontology, and Dublin Core Terms.

DCAT-AP+ is domain-agnostic. It provides a generic set of classes and properties that any domain can import and specialize into its own application profile. ChemDCAT-AP is the first such domain profile, built for chemistry and catalysis research data.

Quick start: What does DCAT-AP+ add?

In plain DCAT-AP, a Dataset can link to a prov:Activity via prov:wasGeneratedBy, but that DCAT-AP's Activity has no specified properties → it is currently a dead end. You are left with dcterms:description (free text), dcat:keyword (free text), and dcat:theme (a very generic controlled vocabulary) to say what a dataset is actually about.

DCAT-AP+ turns that dead end into a structured provenance graph:

# A dataset about an NMR measurement of a chemical sample
id: ex:dataset-001
title: "13C NMR spectrum of aspirin"
description: "13C NMR spectral data for acetylsalicylic acid in CDCl3"
was_generated_by:
  - id: ex:measurement-001
    # an instance of the 13C NMR class from the Chemical Methods Ontology
    rdf_type:  
      id: CHMO:0000595  
      title: "carbon-13 nuclear magnetic resonance spectroscopy"
    evaluated_entity:
      - id: ex:sample-001
        # an instance of "material sample" class from the Ontology for Biomedical Investigations
        rdf_type:
          id: OBI:0000747  
          title: "material sample"
        has_quantitative_attribute:
          - value: 298.0
            has_quantity_type:
              id: qudt:Temperature
            unit:
              id: qudt:K
    carried_out_by:
      - id: ex:spectrometer-001
        # an instance of "JEOL ECX NMR spectrometer" class from OBI
        rdf_type:
          id: OBI:0000625
          title: "JEOL ECX NMR spectrometer"

This is valid DCAT-AP+ instance data. Every class and property is mapped to an established ontology term and instance data can be validated and converted to RDF using the LinkML tooling. The schema itself (dcat_ap_plus.yaml) serves as the single source of truth from which SHACL shapes, JSON Schema, Python/Pydantic data classes, and an HTML schema reference documentation are generated, which means all are guaranteed to be coherent.

Documentation

• Design Patterns & Decisions — The reasoning behind DCAT-AP+ and how its patterns work
• Extension Rules — Rules for how to extend DCAT-AP+ in domain-specific profiles
• Automatic Generation — How the DCAT-AP LinkML schema is built from the official DCAT-AP SHACL shapes
• Schema Reference Documentation — Auto-generated reference for all classes and slots
• Versioning — Versioning rationale
• Projects using DCAT-AP+ — Known adopters and domain profiles

Source code

The LinkML schema, build scripts, and documentation source are on GitHub: nfdi-de/dcat-ap-plus