semantic web - Knowing what RDFA vocabulary to use

Question

How do we know which vocabulary/namespace to use to describe data with RDFa?

I have seen a lot of examples that use xmlns:dcterms="http://purl.org/dc/terms/" or xmlns:sioc="http://rdfs.org/sioc/ns#" then there is this video that uses FOAF vocabulary.

This is all pretty confusing and I am not sure what these vocabularies mean or what is best to use for the data I am describing. Is there some trick I am missing?

Answer 1

There are many vocabularies. And you could create your own, too, of course (but you probably shouldn’t before you checked possible alternatives).

You’d have to look for vocabularies for your specific needs, for example

• by browsing and searching on http://lov.okfn.org/dataset/lov/ (they collect and index open vocabularies),

• on W3C’s RDFa Core Initial Context (it lists vocabularies that have pre-defined prefixes for use with RDFa), or

• by browsing through http://prefix.cc/ (it’s a lookup for typically used namespaces, but you might get an overview by that).

After some time you get to know the big/broad ones: Schema.org, Dublin Core, FOAF, RSS, SKOS, SIOC, vCard, DOAP, Open Graph, Ontology for Media Resources, GoodRelations, DBpedia Ontology, ….