DCAT-AP: How to extend DCAT-AP?

4 years ago

How to extend DCAT-AP?

Issue

The DCAT-AP is cross-border and cross-domain. Applications within a national domain, or applications in a particular domain may have different requirements and therefore may want to define extensions to the basic profile.

Current situation

Currently, two extensions of the DCAT-AP have been defined at the European level. The GeoDCAT-AP for geospatial datasets and the StatDCAT-AP for statistical datasets. Many Member States are also defining national application profiles of the DCAT-AP.

Recommendation

The main rule for extensions is:

  • Any extension of DCAT-AP needs to respect the minimum conformance requirements as defined in section 6 of the specification of DCAT-AP v1.1

Further more specific rules are:

  • Extensions must not widen but may only narrow down the usage notes as specified in DCAT-AP v1.1, so that all information provided according to the extension remains valid for DCAT-AP v1.1
  • Extensions may add classes that are not specified for DCAT-AP; however, an extension should not add classes that are similar to DCAT-AP classes
  • Extensions may add properties that are not specified for DCAT-AP; however, an extension should not add properties that are similar to DCAT-AP properties
  • Extensions may change the cardinalities for properties defined for DCAT-AP v1.1 respecting the following rules:
  • Mandatory properties in DCAT-AP v1.1 must be mandatory in the extension
  • Recommended properties in DCAT-AP v1.1 may be declared optional or mandatory in the extension
  • Optional properties in DCAT-AP v1.1 may be declared recommended or mandatory in the extension
  • Recommended and optional properties in DCAT-AP v1.1 may be removed from the extension
  • Extensions must include all the mandatory controlled vocabularies as listed in section 5 of the specification of DCAT-AP v1.1
  • Extensions may add mandatory controlled vocabularies

 

Rationale

The proposed rules are intended to allow an extension profile to satisfy local or domain-specific requirements while preserving interoperability in a wider European and cross-domain environment,

Example(s)

Examples of existing profiles: