add optional property dct:type to dcat:Distribution

[H-a-g-L]

The open data catalogue of the European Union uses dct:type to classify dcat:Distribution with values from EU Controlled Vocabulary Distribution Type. Available terms include:

• DOWNLOADABLE_FILE
• FEED_INFO
• VISUALIZATION
• WEB_SERVICE

This property can be useful in distinguishing between Distributions available as file download, through a data service or visualisations of datasets.

Would you you consider recommending this as an optional property for DCAT-AP?

[bertvannuffelen]

@ODP-hil , I would consider this in the context of DCAT-AP 1.2.x solely. In the context of DCAT-AP 2.x there are data services, a notion introduced for that purpose.

In https://github.com/SEMICeu/DCAT-AP/issues/144 you find some explorations on this. But in short for me, except for the first one, all are data services.

• Feeds are services that provide information about the changes in the data
• Visualisations, except a static image, are services that allow to explore the data in a complex way. (e.g. dashboards, geoportals, ...)
• web services are obviously data services.

As a general comment, many of our DCAT-AP discussion topics have to do with this kind of questions. Maybe it is good that the community can make a list of cases that mostly are excepted to be data services and others that are distributions. And create so a living guideline on this categorization.

[H-a-g-L]

@bertvannuffelen - Indeed all but the first one are actually data services but dct:type could be useful in defining data service as distribution and the relationship between the two classes (case B.1 in issue #144).

Drawing from example 12 of DCAT 2.0, adding 'dct:type' VISUALIZATION will further clarify that the distribution is a visualisation available via a data service:

:dataset-004
  rdf:type dcat:Dataset ;
    dcat:distribution :dataset-004-png ;
  .

:dataset-004-png
  rdf:type dcat:Distribution ;
  dcat:accessService :figure-service-006 ;
  dcat:accessURL <http://example.org/api/figure-006> ;
  dcat:mediaType <https://www.iana.org/assignments/media-types/image/png> ;
  dct:type <https://publications.europa.eu/resource/authority/distribution-type/VISUALIZATION> ;
  .

:figure-service-006
  rdf:type dcat:DataService ;
  dct:conformsTo <http://example.org/apidef/figure/v1.0> ;
  dct:type <https://inspire.ec.europa.eu/metadata-codelist/SpatialDataServiceType/view> ;
  dcat:endpointDescription <http://example.org/api/figure-006/params> ;
  dcat:endpointURL <http://example.org/api/figure-006> ;
  dcat:servesDataset :dataset-004 ;
  .

A list of cases drawn by the community will also be useful in eventually enriching the Distribution Type Authority Table and possibly advocate the creation of a Data Service Type Authority Table (e.g. API, SPARQL endpoint, download service).

[bertvannuffelen]

During WG 21 Oct 2021, this issue was discussed in the context of the updated UML diagram and an usage guideline for Datasets, Distributions and Data Services.

The adopted proposal was not to include is as a recommended controlled vocabulary.