The W3C RDFa Working Group recently published two new "First Public Working Drafts":
RDFa Core 1.1: Syntax and processing rules for embedding RDF through attributes
http://www.w3.org/TR/2010/WD-rdfa-core-20100422/
XHTML+RDFa 1.1: Support for RDFa via XHTML Modularization
http://www.w3.org/TR/2010/WD-xhtml-rdfa-20100422/
Ivan Herman has a post highlighting some of the new features here
http://ivan-herman.name/2010/04/22/rdfa-1-1-drafts/
And I wrote a few notes along similar lines on our weblog
http://efoundations.typepad.com/efoundations/2010/04/rdfa-11-drafts-available-from-w3c.html
One of the new features introduced is the RDFa profile, which is a mechanism for defining (what I tend to think of as) a shared set of "shortcuts" which can make the creation of RDFa data a little less verbose for the data provider. Those "shortcuts" are of two forms:
1. Prefix mappings
A prefix mapping maps a CURIE prefix to a ("base") URI (e.g. "dcterms" to "http//purl.org/dc/terms/") so that a data provider can reference a profile instead of declaring a set of mappings individually in their document.
2. Term mappings
A term mapping maps a character string to a URI (e.g. "subject" to "http://purl.org/dc/terms/subject") so that a data provider can use that term, instead of a CURIE or a URI, to refer to a property, datatype or class.
Note there's no constraint on the form of the URIs that can be referenced within a single RDFa profile: a single RDFa profile might provide prefix mappings or term mappings for a mix of URIs owned by W3C, DCMI or by some other party, if such a combination is commonly used by implementers.
I noticed that the owners of the Good Relations ontology
http://www.heppnetz.de/projects/goodrelations/
have now made available a short RDFa profile
http://www.heppnetz.de/grprofile/
which defines a set of prefix mappings, for their own RDF vocabulary and for several other vocabularies that are typically used by Good Relations data providers alongside the GR vocabulary - including prefix mappings for "dc" and "dcterms". That profile doesn't provide any term mappings.
I do recognise that the W3C documents are early working drafts and features are liable/likely to change - and indeed I noticed a comment from Jeni Tennison expressing concerns about the profile feature, particularly given the constraints of browser security rules on Javascript-based RDFa parsers:
http://lists.w3.org/Archives/Public/public-rdfa-wg/2010Apr/0189.html
so there's no guarantee that RDFa profiles will be carried through the process in their current form.
But all the same, I wondered whether, as a provider of some very widely used vocabularies, DCMI might consider making available one or more simple RDFa profiles, making it clear that they are based on draft specifications - maybe just prefix mappings like the Good Relations example, to start with at least, either just for DCMI's own vocabularies, or (perhaps more usefully) for DCMI's own vocabularies plus a few others widely used in combination with them (RDF, RDFS, OWL, XSD, FOAF?)
I think doing this would be a visible sign of DCMI's engagement with the RDFa WG and the RDFa development process and a signal to the RDFa community that we are "keeping up with" these developments. And I think it could also serve to raise the visibility of RDFa within the DCMI community, which is something we've mentioned needs some attention.
And alongside the Good Relations profile, it could also provide another quite visible public example for implementers to begin to explore some of the issues around the use of multiple profiles, precedence rules, and so on.
Pete
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Pete Johnston
Technical Researcher
Eduserv
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