[tdwg-guid] Need for citation information in GUID metadata

Ricardo Scachetti Pereira ricardo at tdwg.org
Wed Nov 7 02:48:18 CET 2007

    Please see my comments in line below.

Bob Morris wrote:
> The problem that nobody will take a position on is this:
> Is the metadata on an image file, or on an image?
I don't want to dismiss this as a simple problem. We've been trying to 
knock it down for a long time now. However, I keep wondering why can't 
we just include information from both (image and image file) in the 
metadata by using different predicates in each case. See an example below.
> Even---or especially if---you stick to DC, you have a problem about
> what things are part of a description.  If the metadata is about the
> file, then it is reasonable to express, e.g. that it has 1200x800
> pixels, encoded as jpeg but perhaps not that it is a a picture of a
> flea biting a dog.  If the image is being described, the reverse might
> hold.
Couldn't we say the following about an image?

    <tdwg:Image rdf:about="urn:lsid:example.com:image:1234">
       <dc:title>Picture of my dog Scratchy</dc:title>
       <dc:subject>A picture of a flea biting my dog.</dc:subject>
       <dc:description>A description of a flea biting my dog. You get 
the idea, but an image is worth a thousand words...</dc:description>

Even though I bet the RDF isn't valid, I hope you get the point that 
each predicate refers to either the file or the image, but not both.

If some of these predicates aren't suitable, we can always use some 
other vocabularies (EXIF?). If you want to refer to what's in the 
picture, we can somehow point to our familiar biodiversity information 
objects: taxon name, observation, specimen, etc.

Is there a case where this can't be done?

> ... rendering clients probably
> desperately need the pixel size and also information about where to
> find other sizes of the "same" image.
That's a different problem. We had agreed that LSIDs can't be used if 
the number of representations of an image is infinite or just very 
large. Should we be looking at OpenURL or just Web services (and WSDL)?? 
But that's a little advanced for our simple discussion thread, isn't it?

So, is this a feasible solution, or is there a class of counter examples 
that I'm missing completely?



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