Hi Douglas,
> This discussion is interesting as the current draft of the
> DC-in-RDF [1] also uses rdf:type for syntax encoding schemes,
> rather than rdf:datatype (e.g. see section 2.3.13.2).
I think that document was written before the work on RDF datatyping was
finished, BTW.
> I
> guess we have now moved on to recognising that syntax
> encoding schemes only apply to representations (e.g. value
> strings), not the value itself...
>
> Does this mean we are now in a position to change the draft
> guidelines for syntax encoding schemes from:
> <dc:date>
> <dcterms:W3CDTF>
> <rdf:value>1999-09-25T14:20+10:00</rdf:value>
> </dcterms:W3CDTF>
> </dc:date>
> to this?:
> <dc:date
> rdf:datatype="dcterms:W3CDTF">1999-09-25T14:20+10:00</dc:date>
I think the value of the rdf:datatype attribute in RDF/XML would be a
URI rather than an XML QName, but leaving that aside, the question is
whether we can change the use of the URI:
http://purl.org/dc/terms/W3CDTF
So that URI far been used to denote a class but not a datatype; can we
now state that that URI denotes a literal datatype? A datatype is by
definition also a class, I think, but it's a particular sort of class.
See http://www.w3.org/TR/rdf-concepts/#section-Datatypes
I don't know the answer, but I'm hesitant to say we can just make that
change in the use of the URI i.e. I wonder whether we may need to coin a
new URI for the datatype (or use one provided elsewhere - though I seem
to recall XML Schema doesn't provide anything that corresponds to
W3C-DTF).
But I think we really need the opinion of someone expert in RDF
datatyping to make that judgement.
> I'd also like to raise a related issue in the DCAM: Syntax
> encoding scheme URI and value string language are only
> available for value strings - is there a reason these are not
> available to rich representations? If I have embedded two
> bitstreams - one a GIF with a word in English and the other a
> JPEG with a word in another language, I am unable to indicate
> the syntax encoding scheme or language for these so I don't
> know which is which.
If you want to say that image A is an image of an English language word
"thing" and image B is an image of the Spanish word "cosa", then I think
you'd have to create a description of that image as a resource, and then
say something like
your:imageA some:represents "thing"@en .
your:imageB some:represents "cosa"@en .
Pete
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