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

Donald Hobern dhobern at gbif.org
Wed Nov 7 10:39:39 CET 2007

I thoroughly agree with Ricardo - surely this is what any normal user 
would expect.  They would get the technical metadata indicating size, 
etc. AND information on the significance of the image concerned - 
potentially referencing ontologies (if for example the image serves as a 
depiction of a character state), taxon concepts (via LSID), specimen 
records (via LSID), etc. as well as including a text description of what 
the image represents.

All of this information should be supported - we need the applicability 
statements to document how DC and other standards should be used to make 
this possible.



Ricardo Scachetti Pereira wrote:
>    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?
> <rdf:RDF>
>    <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>
>       <dc:identifier>urn:lsid:example.com:image:1234</dc:identifier>
>       <dc:format>image/jpeg</dc:format>
>       <tdwg:imageDimensions>1200x800</tdwg:ImageDimensions>
>    </tdwg:Image>
> </rdf:RDF>
> 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?
> Cheers,
> Ricardo
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Donald Hobern (dhobern at gbif.org)
Deputy Director for Informatics 
Global Biodiversity Information Facility Secretariat 
Universitetsparken 15, DK-2100 Copenhagen, Denmark
Tel: +45-35321483   Mobile: +45-28751483   Fax: +45-35321480

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