Re: GRDDL in non-HTML XML - how, exactly?

On Mon, 2005-03-21 at 15:55 +0100, Chris Lilley wrote:
> Hello public-rdf-in-xhtml-tf,
> 
> In section 3 of GRDDL (I was reading the 13 April 2004 version)
> http://www.w3.org/TR/grddl/#grddl-xml
> 
> The first two paragraphs seem to contradict each other
> 
> >> The GRDDL profile mechanism is a special case of GRDDL designed to
> >> fit within the syntax of XHTML 1.0. The general form of GRDDL is an
> >> attribute suitable for use with a wide variety of XML dialects.
> 
> OK, cool, so I read on to find out how to do that ...
> 
> >> Use of the interpreter attribute in the
> >> http://www.w3.org/2003/g/data-view# namespace on the root element of
> >> an XML document indicates that RDF statements that result from
> >> transformation of the HTML document to RDF by designated algorithms
> >> are part of the document's meaning.
> 
> "the HTML document"? What if my XML is *not* HTML? Is 'the HTML
> document' just a typo?

yes... fixed in
 http://www.w3.org/2004/01/rdxh/spec#grddl-xml
 $Revision: 1.58 $

> To be specific, how would I change this example
> http://www.w3.org/TR/SVG11/metadata.html#Example
> 
> to say that the content of the metadata element is part of the documents
> meaning? Do I merely add
> 
> xmlns:grddl="http://www.w3.org/2003/g/data-view#"
> grddl:interpreter="what, exactly, goes here"

yes...

   xmlns:data-view="http://www.w3.org/2003/g/data-view#"
   data-view:transformation="http://www.w3.org/2003/g/embeddedRDF.xsl"

You can see the result at
  http://www.w3.org/2003/g/svgc-ex/svg_meta_ex.svg
It works with http://www.w3.org/2003/g/svgc-ex/glean.py ala...

$ python glean.py --output ,svgm.rdf
http://www.w3.org/2003/g/svgc-ex/svg_meta_ex.svg

xsltproc spews complaints about the SVG namespace document
(it's HTML, not XHTML) but you can disregard those diagnostics;
the resulting ,svgm.rdf has the right answer. (I hope we'll
upgrade the SVG namespace document to RDDL or the like soon.)

I tried it in the online service...
  http://www.w3.org/2004/01/rdxh/grddl-xml-demo
but I it fails in a way that I don't understand. (Dom?)


> I read
> >> The value of the grddl:interpreter attribute designates a list of
> >> algorithms by URI reference
> 
> It seems to point to an xsl stylesheet, not a list of algorithms.

As Dom explained, an XSLT stylesheet is a representation of
an algorithm.

> I would also like to know how to GRDDLize these examples
> 
> http://www.w3.org/TR/SVG11/coords.html#GeographicCoordinates
> 
> if that turns out to be different.

Not much. I did the 1st and 2nd ones...
http://www.w3.org/2003/g/svgc-ex/coord_meta1.svg
http://www.w3.org/2003/g/svgc-ex/coord_meta2.svg

On the 3rd one I get an RDF parsing error...

RDF.RedlandError: property element 'CoordinateReferenceSystem' has
multiple object node elements, skipping.

> Please note also that SVG is structured, so a single SVG document
> instance can have several logical parts and each of these can have its
> own metadata element. How do I indicate that the metadata applies to
> just a particular part of the document (ie, the parent of the metadata
> element?

RDF is context-free... the subjects of the statements are explicit.
the rdf:about attribute is used to say what statements are about.

In the 2nd example, I see this bit of RDF:

        <rdf:Description>
          <!-- In case of a well-known Coordinate Reference System
               an 'Identifier' is enough to describe the CRS -->
          <crs:CoordinateReferenceSystem svg:transform="rotate(-90) scale(100, 100)">
            <crs:Identifier>

That just says "there is a coordinate reference system." It doesn't
say what the relationship between that coordinate system and this
SVG file is.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E

Received on Wednesday, 23 March 2005 23:09:38 UTC