Ivan said:
> I read the document from an RDF point of view, and my comment
> is probably for clarification only (but it may be worth
> either adding this to the document or having a separate,
> explanatory document).
>
> - The document defines a rich representation. I tried to
> translate a rich representation into RDF, and I am not sure
> it is correct. What I came up with as an example (using
> Turtle syntax) is:
>
> dc:blabla [
> dcterms:format [
> rdf:type ex:MediaType;
> dc:label "image/jpeg";
> ]
> rdf:value "base64 encoded bytes of the image".
> ].
>
> ie, the property using a rich representation refers to a
> blank node that includes a reference to a media type and the
> value.
Yes, that is pretty much how I envisaged the rich representation notion
being represented using RDF. Actually, given that (according to the
DCAM) a single statement may provide multiple rich representations for a
single value, I think there may be an additional node and arc involved.
So if, say, I want to say that a book was authored by some entity
represented by a JPEG and by a GIF, then I think in RDF, that would look
something like (gulp):
_:mybook
a ex:Book ;
dcterms:creator [
rdfs:seeAlso [
dcterms:format [
rdf:type ex:MediaType ;
rdfs:label "image/jpeg" ;
] ;
rdf:value "base64 encoded bytes"^^xsd:base64Binary
] ;
rdfs:seeAlso [
dcterms:format [
rdf:type ex:MediaType ;
rdfs:label "image/png" ;
] ;
rdf:value "base64 encoded bytes"^^xsd:base64Binary
]
]
.
(Probably with some question marks over whether we use
rdfs:seeAlso/rdf:value or some other properties?)
> The ex:MediaType is defined, in [1], as a class, hence
> the extra blank node. It is also not clear how one defined a
> particular media type..
Are their URIs for the IANA registered MIME types?
I found http://www.w3.org/2001/tag/2002/01-uriMediaType-9 expressing the
desirability of having some URIs, but I'm not sure whether any were
assigned/are in widespread use.
Pete
---
Pete Johnston
Technical Researcher, Eduserv Foundation
Web: http://www.eduserv.org.uk/foundation/people/petejohnston/
Weblog: http://efoundations.typepad.com/efoundations/
Email: [log in to unmask]
Tel: +44 (0)1225 474323
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