References
This issue has been reported by Antonio Rotundo.
http://joinup.ec.europa.eu/mailman/archives/dcat_application_profile-geo/2015-August/000190.html
Explanation
Draft 6 of the GeoDCAT-AP specification, in its Annex II.8, proposes to use the property dcat:theme for the INSPIRE metadata element "Keyword value" (only in case that the controlled vocabulary for the keywords is the one of the INSPIRE spatial data themes). However, it is not conformant to the requirement given by DCAT-AP in its Annex II.
Antonio proposes to move the property dcat:theme to the extended profile in order to use the codelist in INSPIRE registry (proposed even as controlled vocabulary in chapter 6) to express the keywords.
This issue has been clarified with the DCAT-AP WG. The DCAT-AP recommendation is not exclusive, i.e. dcat:theme must be used with the theme vocabulary in Annex II of the DCAT-AP spec., but this does not exclude the possibility of having other instances of dcat:theme using other vocabularies/thesauri. There is a statement in the Conformance section which allows additional assertions with dcat:theme that use other theme vocabularies (which then may or may not be understood by data receiver):
For the properties listed in the table in section 5, the associated controlled vocabularies MUST be used. Additional controlled vocabularies MAY be used.
Related issues
- GeoDCAT-AP: controlled vocabulary for marine regions
- GeoDCAT-AP: Controlled vocabulary for location information
- GeoDCAT-AP: Controlled vocabulary for discipline
- GeoDCAT-AP: Controlled vocabulary for spatial resolution
- GeoDCAT-AP: Controlled vocabulary for spatial representation type
- GeoDCAT-AP: Keyword controlled vocabulary
- GeoDCAT-AP: Controlled vocabularies for frequencies
Comments
I thought it was clear. But seeing the wording in the Draft 7 (in section 5.2 table 2 page 18, section 6 table 4 page 26 and Annex II section II.8) I still have some doubts on this issue.
The mentioned statement in the Conformance section in DCAT-AP means for me that the controlled vocabulary represented by the INSPIRE themes should be considered in addition and not in place of that one foreseen for the property dcat:theme in DCAT-AP.
In the GeoDCAT-AP Draft 7 the controlled vocabulary required in DCAT-AP is not at all mentioned.
I think that the wording for the requirements concerning the property dcat:theme (used for the INSPIRE metadata element "keywords") in GeoDCAT-AP should be analogous, e.g., to the property dct:accrualPeriodicity, used for the INSPIRE metadata element “maintenance frequency” (see section 6, table 4, page 28 and Annex II, section II.27) for which the related vocabulary in DCAT-AP is mentioned and required and, in addition, the code list of ISO maintenance frequency codes is recommended.
So, if my interpretation is right, the possible solution could be to foresee two instances of dcat:theme, one for which the controlled vocabulary required in DCAT-AP is used and the other one for which the INSPIRE themes vocabulary is used. The former instance could be even automatically generated, e.g. by the XSLT script, on the base of an appropriate mapping between the two vocabularies. In this regard, I made an attempt of such a mapping (please consider it a very preliminary excercise), see attached file.
Thank you, Antonio, for pointing this out a second time. Draft 7 (v0.45) is updated to reflect this. The text now reads as follows:
For keywords whose controlled vocabulary is the one of the INSPIRE spatial data themes the dcat:theme predicate must be used. For conformance to DCAT-AP – i.e. the GeoDCAT-AP Core Profile – the Data themes Name Authority List must be used (Table 3 contains a suggested mapping between the INSPIRE data themes and the Data themes NAL). As part of the GeoDCAT-AP Extended Profile, an additional triple can be added using the corresponding URI for the INSPIRE spatial data theme in the INSPIRE Registry.
For keywords associated with other controlled vocabularies the dcat:theme predicate must be used. The controlled vocabulary must be expressed as a skos:Concept associated with a skos:ConceptScheme, and annotated with the textual content and reference date(s) in the relevant INSPIRE metadata elements. For conformance to DCAT-AP – i.e. the GeoDCAT-AP Core Profile – a mapping with the URIs of the Data themes Name Authority List must be used. As part of the GeoDCAT-AP Extended Profile, additional triples can be added using other controlled vocabularies. In the latter case, the skos:Concept and skos:ConceptScheme can be blank nodes (i.e., it is possible that no URIs are used to denote them).
Dear Stijn,
it seems fine now.
Only a comment: since I made the mapping before the final draft of DCAT-AP was published, I noticed that some data themes NAL labels are changed in the final version of vocabulary. So the following labels should be updated in table 3:
Best regards,
Antonio
The relevant section has been revised in v0.46 as described in:
http://joinup.ec.europa.eu/mailman/archives/dcat_application_profile-geo/2015-November/000270.html