DCAT-AP and its extensions: Context and evolution

One of the main challenges that arise when addressing an Open Data initiative is to define the information architecture and facilitate interoperability between data catalogs published by different portals on the Web. In order to solve this challenge, the World Wide Web Consortium (W3C) published the Data Catalog Vocabulary (DCAT), an RDF vocabulary to describe data catalogs based on 3 key concepts: catalog, dataset and distribution.

Based on this vocabulary, and within the JoinUP project, a collaborative platform created by the European Commission, an international group of experts developed the DCAT Application profile for data portals in Europe (DCAT-AP): a specification that describes restrictions (such as properties range) on the DCAT model. The objective is to facilitate homogenization and cross-searching, using metadata, between different European data portals generated by public sector and placed at citizens disposal for reuse.

The report DCAT-AP and its extensions: context and evolution, developed within the Aporta Initiative framework, arose to ​​ contextualize and delve into DCAT-AP, and DCAT vocabulary. The report includes a description of both publications, as well as a definition of the agencies and institutions involved in its definition.

DCAT-AP extensions and modifications

Based on DCAT-AP, sector extensions have been developed, some of the most relevant in specific areas of application are described in this report: DCAT-AP HVD, DCAT-AP extension for the description of high-value data, GeoDCAT-AP, focused on the exchange of descriptions of geospatial datasets and services, StatDCAT-AP, an extension of DCAT-AP for the exchange of descriptions of statistical datasets and services, MLDCAT-AP extending DCAT-AP in the field of machine learning, and BRegDCAT-AP for the description of fundamental aspects of public administrative records.

Since its appearance and throughout these years, practically all the Member States of the European Union have extended the DCAT-AP application profile to meet their needs. Special emphasis is placed on Spain, where there is the peculiarity that the "extension" - the Norma Técnica de Interoperabilidad de Reutilización de recursos de información (NTI-RISP) - preceded the DCAT-AP specification itself, which at the time of writing has evolved into the DCAT-AP-ES reference extension.. (NTI-RISP) establishes the common framework for opening and using documents and information resources produced or held by public administrations. This technical standard aims to ensure the persistence of information and the use of formats, and to promote appropriate terms and conditions of use. The NTI-RISP standard predates the first versions of DCAT and DCAT-AP, which has resulted in some differences.

Finally, some DCAT-AP extensions implemented by the different Member States are listed for reference.