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URIs for Concept & ConceptScheme - best practice?

From: Simon Cox <simon.cox@jrc.ec.europa.eu>
Date: Fri, 14 May 2010 14:41:39 +0200
To: <public-esw-thes@w3.org>
Message-ID: <6EA9A905E1C845D4852F8AC5E356902A@H07.jrc.it>
I'm thinking about identifier policies for ontologies and concept-schemes. 
In work that I have done previously on identifier policies for Open
Geospatial Consortium and for Commission for Geoscience Information we used
the identifier scheme largely as a way to enforce certain governance
arrangements for resource publication. The general principle is that a URI
is composed of a number of fields. A new URI can only be minted if the
values in all the fields are valid; the allowable value for each field must
come from a specific register; and different parties are authorized to
modify different registers. So we end up with a delegation system. This kind
of scheme uses the URI structure for internal governance purposes, within
the community. 
But http URIs have a 'path-like' structure which can be interpreted as a
tree. Read in this way, the URI scheme impies certain relationships between
resources, in particular 'ownership' of children by their parents.
Notwithstanding the REST principle that information is in the representation
and not the identifier, Cool URIs can be interpreted by users, and typically
support navigation through tweaking the URI (many refs).  This kind of
scheme is aimed at external users. 
Following this approach: is it smart to have the URI for a SKOS concept to
be just an extension of the URI for the SKOS concept scheme? 
<http://resource.geosciml.org/concept/unit-rank/bed> unit-rank/bed>
skos:inScheme <http://resource.geosciml.org/concept/
<http://resource.geosciml.org/concept/unit-rank> unit-rank>.
I'm assuming slash URIs, since I want the server to do most of the work,
supporting content-negotiation, etc. 
The advantage in this approach is that a casual user can navigate between
parent and child by URI twiddling. 
But possible gotchas are 
(1) it assumes exactly one parent 
   - it requires every concept to be in a scheme
   - it privileges one scheme above any others (though I think there is no
limit on the number of inScheme properties a Concept can have?)
(2) there must be some others
I'd be interested in comments. 

Simon Cox

European Commission, Joint Research Centre 
Institute for Environment and Sustainability 
Spatial Data Infrastructures Unit, TP 262 
Via E. Fermi, 2749, I-21027 Ispra (VA), Italy 
Tel: +39 0332 78 3652 
Fax: +39 0332 78 6325 
 <mailto:simon.cox@jrc.ec.europa.eu> mailto:simon.cox@jrc.ec.europa.eu 

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Received on Friday, 14 May 2010 12:45:48 UTC

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