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Re: DC vs. DCTERMS in initial context

From: Oskar Welzl <lists@welzl.info>
Date: Fri, 31 Aug 2012 13:08:14 +0200
Message-ID: <1346411294.5524.25.camel@jupiter.hormayrgasse>
To: Ivan Herman <ivan@w3.org>
Cc: W3C RDFa Community <public-rdfa@w3.org>, Thomas Baker <tom@tombaker.org>

> As far as I remember, the advice of DCMI (Tom, correct me if I am
> wrong) was to use only /dc/terms in future, [...]
> Personally, I would like to defer the choice to DCMI.

The choice to prefer DCTerms for current/future use is one thing.

The problem arises when you change existing RDFa to RDFa 1.1 and rely on
the initial context. In this case, the RDF output doesn't comply to the
DCMI recommendations. I came across this when I tried to convert the
RDFa 1.0 example in wikipedia [1] to RDFa 1.1, removing XML namespace
declarations while doing so.

I expected the same RDF triples thanks to the initial context, but got 

<http://example.org/john-d/> 
    <http://purl.org/dc/terms/creator> "Jonathan Doe"@en;

instead of the original
<http://example.org/john-d/> 
    <http://purl.org/dc/elements/1.1/creator> "Jonathan Doe"@en;

Now dc:creator (or http://purl.org/dc/elements/1.1/creator) may be used
with literals, so the original RDFa 1.0 was OK.
OTOH, dcterms:creator, according to the user guide [2], must not be used
with literals. I had overrule the initial context and insert the
corresponding prefix into the HTML+RDFa 1.1 example to make it work.

I don't know how many will change from existing markup to 1.1, but if
they do there'll be some more unwanted literals as dcterms:creators out
there. 

Maybe it'd be enough to point this out somewhere. I have no idea how
relevant it will become.

Cheers
Oskar

[1] http://en.wikipedia.org/wiki/RDFa#XHTML.2BRDFa_1.0_example
[2]
http://wiki.dublincore.org/index.php/User_Guide/Publishing_Metadata#dcterms:creator


> Cheer
> 
> Ivan
> 
> On Aug 29, 2012, at 20:42 , Oskar Welzl wrote:
> 
> > I only noticed a few day ago that both dc: and dcterms: are used for 
> > http://purl.org/dc/terms/
> > in the initial context. In most examples or practical uses so far, I've
> > seen dc: being used for 
> > http://purl.org/dc/elements/1.1/
> > instead, making it easy to distinguish between the legacy vocabulary and
> > DCTerms. (Practical example:
> > http://wiki.dublincore.org/index.php/User_Guide/Publishing_Metadata)
> > 
> > 
> > What's the rationale behind this decision in the initial context? 
> > 
> > Oskar
> > 
> > 
> 
> 
> ----
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> FOAF: http://www.ivan-herman.net/foaf.rdf
> 
> 
> 
> 
> 
Received on Friday, 31 August 2012 11:08:49 UTC

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