W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > September 2005

RE: new W3C CDF specs (XHTML +SVG + SMIL +XForms) --- RDF/XML opportunity?

From: Mark Birbeck <mark.birbeck@x-port.net>
Date: Mon, 12 Sep 2005 11:26:16 +0100
Message-ID: <9F96E57A-95C3-49CA-8ED2-F3A6A013BA0B@S009>
To: "'Bjoern Hoehrmann'" <derhoermi@gmx.net>
Cc: <public-rdf-in-xhtml-tf@w3.org>


> * Mark Birbeck wrote:
> >Just because you can use any language you like, doesn't make 
> it extensible.
> >Since you have no way to know what language is being used, 
> then I don't 
> >see how it could really be called 'extensible'?
> >
> >Perhaps if there was an attribute to indicate the type of 
> the metadata, 
> >you could say it was extensible. Something like:
> >
> >  <svg>
> >    <metadata type="application/rdf+xml">
> >      <rdf:RDF...
> >    </metadata>
> >  </svg>
> Excellent remark, indeed, how could we possibly find the RDF 
> fragment in a SVG fragment like
>   <svg:metadata>
>     <rdf:RDF
>          xmlns:rdf = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>          xmlns:rdfs = "http://www.w3.org/2000/01/rdf-schema#"
>          xmlns:dc = "http://purl.org/dc/elements/1.1/">
> ...

Of course if you know what you are looking for in advance then you can find
it. But you talked before of extensibility...to me any meaningful
extensibility would require that you can still parse the metadata, even if
you don't know in advance what you are going to parse. But the only examples
I have seen of metadata in SVG have used RDF/XML, implying anything *but*

> In fact, it's a bit sad, but considering that RDF/XML "is 
> difficult or impossible to validate documents that contain 
> RDF/XML using XML Schemas or DTD's" and "the syntax of 
> RDF/XML is too unwieldy for use", I think replacing it with a 
> superior solution like XHTML-free RDF/A-only XHTML2 documents 
> is the only way forward. Would you be available to write the 
> RFC that moves RFC 3870 to Historic?

I'm losing track of exactly what the target of your sarcasm is, Bjoern.
Perhaps you could help me recalibrate?

Anyway, RDF/XML has not made it into the world of everyday mark-up. Whether
it's personal blogs or major news organisations' sites, RDF/XML is simply
not used. The IPTC for example (the standards body which many of the news
organisations are members of) has bluntly said that RDF/XML is both too
difficult, and too verbose for use in its own languages. We therefore have a
situation where we either ignore the problem, and lose the enormous quantity
of metadata that is in 'everyday' documents, or we try to find a way out.
GRDDL was an attempt to do that, and with respect I believe it is difficult
to make it work. RDF/A was my attempt to try to solve the same problem, and
in my view it does the potential to be generic...and yes, to end where we
came in, it is applicable to SVG.



Mark Birbeck
x-port.net Ltd.

e: Mark.Birbeck@x-port.net
t: +44 (0) 20 7689 9232
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Received on Monday, 12 September 2005 10:26:55 UTC

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