Hi Pete
We here (at AHDS) have been grappling with this problem ourselves. My view
is that it does certainly stretch the 'one-to-one' rule more than I feel
comfortable with. As well I'm not sure that any obvious solution suggests
itself. I feel that its more likely than not that collections are
heterogenous and as such do not lend themselves to easy descriptions of
format. Is it necessary to do this anyway? If a collection is homogenous
then it could be described using dc:format. If its not homogenous then don't
try to describe the format.
cheers
Andrew Wilson
-----Original Message-----
From: DCMI Collection Description Group
[mailto:[log in to unmask]]On Behalf Of Pete Johnston
Sent: 04 May 2005 07:53
To: [log in to unmask]
Subject: Re: Format of items within collection
Any thoughts on this please?
Pete
On Sun, 10 Apr 2005 19:52:57 +0100, Pete Johnston <[log in to unmask]>
wrote:
>I'm conscious that we still have not resolved the issue of how to
>describe the format of items in the collection (see e.g. [1]), and it is
>now urgent that we find a solution.
>
>I think the use of dc:format as a property of the collection for this
>would _not_ be appropriate, because if I do a search like (using SPARQL
>syntax [2])
>
>PREFIX dc: <http://purl.org/dc/elements/1.1/>
>PREFIX dcterms: <http://purl.org/dc/terms/>
>SELECT ?thing
>WHERE (?thing dc:format ?format)
> (?format rdf:value "text/html")
>
>I expect to retrieve a list of resources of format text/html. A
>collection that includes items of format text/html is not itself a
>resource of format text/html.
>
>As I said in that previosu message, I think ideally the "right" way to
>represent this would be something like:
>
>collection:C some:contains item:I .
>item:I dc:format format:F .
>format:F rdf:value "text/html" .
>
>But if we are trying to stick to using properties only of the
>collection, the only way I can think of representing this information
>would be to define a property something like cld:itemFormat
>
>Label: "Item Format"
>Definition: The physical or digital form of an item within the
>collection.
>Comment: Recommended best practice is to select a value from a
>controlled vocabulary (for example, the list of Internet Media Types
>[MIME] defining computer media formats).
>
>N.B. This would _not_ be a refinement/subproperty of dc:format.
>
>In DC CD AP, the property would be repeatable. As for when it should be
>deployed (does the existence of one RTF document in a collection of
>99,999 PDF documents mean that I should say the collection contains PDF
>items?), I guess we'd have to provide some guidelines.
>
>I do wonder whether this is bending the "one-to-one rule" rather more
>than I feel comfortable with, but I don't have any better suggestions.
>
>Any thoughts please?
>
>If we did adopt this approach, then
>
>(a) I think we should re-consider the type vocabulary and use something
>like an itemType property with the DCMI Type Vocabulary for the types of
>the items (as suggested by Ann at [3]) (but we would retain the use of
>dc:type with the other types that distinguish the types of
>catalogue/finding-aid)
>
>(b) I'm not convinced we need to retain the separate use of dc:format in
>the DC CD AP (which is rather vaguely defined/described at present):
>size would be covered by dcterms:extent, and the format of items would
>be covered by this new property.
>
>Pete
>
>[1]
>http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0312&L=dc-collections&T
>=0&F=&S=&P=60
>[2] http://www.w3.org/TR/rdf-sparql-query/
>[3]
>http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0411&L=dc-collections&T
>=0&F=&S=&P=172
>
>-------
>Pete Johnston
>Research Officer (Interoperability)
>UKOLN, University of Bath, Bath BA2 7AY, UK
>tel: +44 (0)1225 383619 fax: +44 (0)1225 386838
>mailto:[log in to unmask]
>http://www.ukoln.ac.uk/ukoln/staff/p.johnston/
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