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Re: Using MIME types in RDF/DAML and Image Metadata

From: Dave Beckett <dave.beckett@bristol.ac.uk>
Date: Sun, 30 Mar 2003 23:51:42 +0100
To: Yarden Katz <katz@underlevel.net>
Cc: www-rdf-interest@w3.org, www-rdf-logic@w3.org
Message-ID: <5689.1049064702@hoth.ilrt.bris.ac.uk>

>>>Yarden Katz said:

[Aside, this message probably didn't need cross posting ]

> Hi,
>   What are some approaches to assign MIME-types to certain RDF or DAML
>   resources?  For example, consider the following:
>     <daml:ObjectProperty rdf:ID="Picture">
>       <rdfs:label>A Picture</rdfs:label>
>       <rdfs:comment>A cute picture class in DAML</rdfs:comment>
>       <rdfs:domain rdf:resource="#SomeObject"/>
>       <rdfs:range rdf:resource="#????"/>
>     </daml:ObjectProperty>

I'm not familiar with the semantics of daml:ObjectProperty (or the
OWL equivalent), however ...

>   An agent attempting to render RDF data has no way of knowing that
>   resources linked to using the above property are images and are to
>   be handled as such.  How can these meaning be conveyed in RDF?  The
>   obvious method seems to be to assign a MIME type such as
>   "image/jpeg" as the range of this property, but I do not know how
>   that can be expressed.  Googling showed up a seemingly relevant link
>   "Mapping Between Content-Types (MIME types) and URIs" from
>   <http://rdfig.xmlhack.com/2001/05/09/2001-05-09.html> but it is
>   broken.  Any ideas you may have on how to attach this elementary
>   problem would be great, whether involving usage of MIME or not.

A quick google finds:

  Mapping between URIs and Internet Media Types
  TAG Finding 8 April 2002 (Revised 27 May 2002)


which is probably the best current description and set of ideas on
this problem.

The other way uses familiar and well deployed Dublin Core vocabulary
an it's dc:format property.  It takes as primary recommend value the
IMT / MIME Type as a literal.  You might be able to do some inference
magic to imply that all your 'Picture's have the dc:format
"image/jpeg".  Otherwise you'd need to put it in the instance data.

See http://dublincore.org/documents/1999/07/02/dces/
and many DC and RDF apps use this already.

>   I have a second question that's related to the above: is there some
>   uniform way to note coordinates on an image (similar to an image
>   map) in RDF?  For example, expressing something a long the lines of
>   "Instances of Object X should be placed in coordinate (X, Y)"  The
>   most relevant link I found was:
>   <http://www.w3.org/2001/08/rdfweb/foafwho/imagemap/> but it does not
>   show an RDF representation of an image map, only the plain HTML one.

Sorry, I've no info on this question.

Received on Sunday, 30 March 2003 17:54:23 UTC

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