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I am describing media elements and I don't know whether to use skos:subject or dc:subject to describe a topic of a media item. I want to use a class in the range of the relation to be able to find media items of the same topic and to describe the topic. I read that skos:subject is deprecated, and dc:subjct has a text field as range (right?). Could I still use dc:subject or there is any other vocabulary to describe this? Thanks!

flag	asked Apr 29 at 13:49 Ale 127●5

ldodds · Accepted Answer · 2010-06-10 22:03:02Z UTC

I would strongly recommend the following pattern:

Use dcterms:subject to refer to a resource describing a topic, e.g. a skos:Concept
Use foaf:topic or foaf:primaryTopic to refering to a specific entity that is the topic of something, e.g. dbpedia:London

dcterms:subject is intended to be used to refer to entries in a controlled vocabulary and SKOS is the best practice way to publish those.

foaf:topic (and related terms) are for relating together resources.

Dan Brickley has a nice diagram that illustrates this usage:

http://www.flickr.com/photos/danbri/3282565132/

I drew on that whilst putting together this presentation:

http://news-linked-data.googlegroups.com/web/adopting-linked-data.pdf?gda=iHbwYUsAAAB_SOPOY0aTVAevbtfYPixo_7tWf4wQAeMpgmDNdAxib27OIe4YMq77XI-lVZNX4XP0ZikYB6FiY_eFHi023WSsBkXa90K8pT5MNmkW1w_4BQ

Dave Reynolds · Answer 2 · 2010-04-29 14:28:00Z UTC

skos:subject is indeed deprecated in favour of dc:subject.

With the modern version of DC, DC Terms, http://purl.org/dc/terms/subject, then using a resource as the value of dc:subject is fine.

Using a class rather than a skos:Concept as the classification can be OK but there is a difference between the class of say Lions and the class of media that are about Lions. See the Semantic Web Best Practice note for a discussion on this: http://www.w3.org/TR/swbp-classes-as-values/

Comment Bot · Answer 3 · 2010-04-29 14:39:02Z UTC

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Dublin Core was updated in 2008, and has (happily) moved away from the ubiquitous literals of dc10 and dc11. In your case move to using the current namespace http://purl.org/dc/terms/ (i.e. http://purl.org/dc/terms/subject) and you'll find "[t]his term is intended to be used with non-literal values" (http://dublincore.org/documents/dcmi-terms/#terms-subject).

edited Apr 29 at 14:39

answered Apr 29 at 14:18

Comment Bot
1,162●1●8

	Cool, I saw there was no resriction when I imported the DC ontology, and I hestite. Thanks for clarify my doubt :) – Ale Apr 29 at 14:29
	You're not alone in being confused. The older DC didn't really commit to an RDF-ish model, and the requirements of values was rather vague. The new work is, as you can see, much better aligned with RDF. The deprecation of skos:subject is closely related to this decision. – Comment Bot Apr 29 at 14:37

Yannick · Answer 4 · 2010-04-29 16:33:13Z UTC

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maybe foaf:topic could also be of interest, since it has a foaf:Document as domain, and a owl:Thing as range

answered Apr 29 at 16:33

Yannick
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Nathan · Answer 5 · 2010-04-30 20:09:54Z UTC

dcterms:subject is definately a good choice, however it's worth considering sioc:topic too, in general usage dcterms:subject is often used with literal values by the broader web community, whereas sioc:topic is a subclass of dcterms:subject and generally used only with URIs.

Describe a topic of a concept

5 Answers