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lcsh.info RDFa SKOS and content negotiation - use of RDF-style # IDs in RDFa?

From: Dan Brickley <danbri@danbri.org>
Date: Tue, 30 Sep 2008 12:50:02 +0200
Message-ID: <48E2045A.4040801@danbri.org>
To: RDFa <public-rdf-in-xhtml-tf@w3.org>, "www-tag@w3.org WG" <www-tag@w3.org>
Cc: Ed Summers <ehs@pobox.com>


Looks like http-range-14 still haunts us. I'm looking for some best 
practice advice for using "#blahblah" URI IDs in RDFa content...

Backstory -

Edd Summers has put up a great site at http://lcsh.info/

It has one page for each concept listed in the Library of Congress 
Subject Headings, eg. http://lcsh.info/sh85112589 is a URI for a 
document about the LCSH heading "Religion and the Humanities".

There is RDFa in the HTML page, as well as a complete NTriples zip-file 
download of the dataset. The RDFa uses a #concept URI to identify the 
abstract concept that the document is describing with SKOS.

<div class="concept" about="http://lcsh.info/sh85112589#concept" 
typeof="skos:Concept">

The document also has an RDF/XML representation available by content 
negotiation. While the triples differ a little (Ed - is this a bug?), 
they all talk about the SKOS concepts via identifiers that take the main 
page's URI and append '#concept'.

Is it TAG-acceptable to use a URI in this manner, when 
http://lcsh.info/sh85112589 is the URI for a document available in RDFa 
XHTML rather than RDF/XML? What does 
"http://lcsh.info/sh85112589#concept" name? How do we 'follow our nose' 
here? Should the media type definition for RDFa allow the assignation of 
URIs to things other than chunks of markup?

Does anyone have a suggestion for how if at all this should be done 
differently? My sense is that the HTML spec as-is doesn't license us to 
assign URIs in this way. And since #foo is to be interpreted w.r.t. to 
the (set of?) media types we get back as HTTP representations, there 
seems to be a tension here between using conneg and using rdfa and 
avoiding having to do http 303 redirects...

cheers,

Dan



curl -s http://lcsh.info/sh85112589 | rapper -i rdfa - file:

rapper: Parsing file <stdin> with parser rdfa and base URI file:
rapper: Serializing with serializer ntriples and base URI file:

<file:> <http://www.w3.org/1999/xhtml/vocab#alternate> 
<http://lcsh.info/sh85112589.rdf> .
<file:> <http://www.w3.org/1999/xhtml/vocab#alternate> 
<http://lcsh.info/sh85112589.n3> .
<file:> <http://www.w3.org/1999/xhtml/vocab#alternate> 
<http://lcsh.info/sh85112589.json> .
<http://lcsh.info/sh85112589#concept> 
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type> 
<http://www.w3.org/2004/02/skos/core#Concept> .
<http://lcsh.info/sh85112589#concept> 
<http://www.w3.org/2004/02/skos/core#prefLabel> "Religion and the 
humanities" .
<http://lcsh.info/sh85112589#concept> 
<http://www.w3.org/2004/02/skos/core#altLabel> "Humanities and religion" .
<http://lcsh.info/sh85112589#concept> <http://purl.org/dc/terms/created> 
"1986-02-11" .
<http://lcsh.info/sh85112589#concept> 
<http://purl.org/dc/terms/modified> "1986-02-11T00:00:00" .
rapper: Parsing returned 8 triples


curl -H "Accept: application/rdf+xml" -s http://lcsh.info/sh85112589 | 
rapper -i rdfxml - file:

rapper: Parsing file <stdin> with parser rdfxml and base URI file:
rapper: Serializing with serializer ntriples and base URI file:

<http://lcsh.info/sh85112589#concept> 
<http://www.w3.org/2004/02/skos/core#altLabel> "Humanities and 
religion"@en .
<http://lcsh.info/sh85112589#concept> 
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type> 
<http://www.w3.org/2004/02/skos/core#Concept> .
<http://lcsh.info/sh85112589#concept> <http://purl.org/dc/terms/created> 
"1986-02-11"^^<http://www.w3.org/2001/XMLSchema#date> .
<http://lcsh.info/sh85112589#concept> 
<http://www.w3.org/2004/02/skos/core#prefLabel> "Religion and the 
humanities"@en .
<http://lcsh.info/sh85112589#concept> 
<http://www.w3.org/2004/02/skos/core#broader> 
<http://lcsh.info/sh85062913#concept> .
<http://lcsh.info/sh85112589#concept> 
<http://purl.org/dc/terms/modified> 
"1986-02-11T00:00:00"^^<http://www.w3.org/2001/XMLSchema#dateTime> .
<http://lcsh.info/sh85112589#concept> 
<http://www.w3.org/2004/02/skos/core#inScheme> <http://lcsh.info/> .
rapper: Parsing returned 7 triples
Received on Tuesday, 30 September 2008 10:50:44 GMT

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