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RE: Spatial datatypes in OWL/RDF

From: John Goodwin <John.Goodwin@ordnancesurvey.co.uk>
Date: Tue, 15 Apr 2008 11:17:14 +0100
Message-ID: <6A035FEF345E064E893D784097F8BC7F024A1775@OSMAIL.ordsvy.gov.uk>
To: "Fink, Clayton R." <Clayton.Fink@jhuapl.edu>, <public-owl-dev@w3.org>
Thanks for your reply Clay, however you really don't want to trust
ontologies those Ordnance Survey people write...they have no idea what
they are talking about [1]

 

I think there might be two issues here - one is doing RCC8 type
reasoning within OWL, i.e. reasoning about "part of", "touches" etc. and
the other is how do we (in a standard way) reference and use spatial
datatypes in OWL/RDF. I know the latter may be a way off yet, but it
would be nice to start thinking about it. It would certainly be nice to
see OWL instance stores/triplestores in the future being able to handle
spatial datatypes in an analogous way that spatial databases can. 

 

John

 

 

[1] - it's ok...I am one of those Ordnance Survey people, and one of
those geo-incubator people :-)

________________________________

From: Fink, Clayton R. [mailto:Clayton.Fink@jhuapl.edu] 
Sent: 14 April 2008 14:27
To: John Goodwin; public-owl-dev@w3.org
Subject: RE: Spatial datatypes in OWL/RDF

 

See this for a particular application of some of these ideas:
http://ebiquity.umbc.edu/_file_directory_/resources/215.pdf

 

I used an ontology that Harry Chen developed (SOUPA - unfortunately it's
disappeared) to try out spatial reasoning.  As I remember it it had
predicates like "inOrAround" and "within" to test the spatial
relationships of geotagged entities.

 

See here for the (now closed) W3C Geospatial Incubator Group report :
http://www.w3.org/2005/Incubator/geo/XGR-geo-ont-20071023/
<http://www.w3.org/2005/Incubator/geo/XGR-geo-ont-20071023/> .  They
reference an ontology developed by the Ordnance Survey for geospatial
relationships at
http://www.ordnancesurvey.co.uk/ontology/SpatialRelations.owl
<http://www.ordnancesurvey.co.uk/ontology/SpatialRelations.owl> .

 

I get the impression the there has been a lot of activity in this area
but no consensus (yet) on a single ontology or vocabulary.

 

As far as integrating these concepts into SPARQL I think it's more along
the lines of a trivial engineering problem in terms of writing functions
like touches().  The non-trivial aspect is coming up with an ontology
that people would find useful.  An initial cut might be to use the
SpatialRelations ontology referenced above and develop some Jena rule
functions that would work with Jena rules and the Jena rule reasoner.
I mention Jena because it's the only tool that I know really well.  The
various SPARQL query engines should allow you to write custom functions,
I would think.  

 

Clay

 

________________________________

From: public-owl-dev-request@w3.org
[mailto:public-owl-dev-request@w3.org] On Behalf Of John Goodwin
Sent: Monday, April 14, 2008 6:18 AM
To: public-owl-dev@w3.org
Subject: Spatial datatypes in OWL/RDF

 

Hi all,

 

Working with spatial data it would be very useful if we could extend
RDF/OWL to include spatial datatypes. The Open Geospatial Constortium
(OGC) provides standards for spatial datatypes and these are common used
in GML file (Geographic Markup Language - the standard for exchanging
spatial data). 

 

Could  these spatial datatypes could be used in OWL and/or RDF in the
same way that current XML Schema datatypes are used (in fact one of the
early version of GML was encode in RDF). It would be nice to see spatial
extension to triples stores (in an analogous way to spatial extensions
of relational databases) that allow SPARQL queries of the form:

 

Select ?a ?b

Where

{ 

            ?a hasGeometry ?g1 .

            ?b hasGeometry ?g2 .

            FILTER (touches(g1,g2))

}

 

(find all a and b where a and b have touching geometries).

 

I'm curious to know what the issues are with this from a logical point
of view, or is it just a non-trivial engineering problem?

 

John

 

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Unless stated otherwise, the contents of this email are personal to the writer and do not represent the official view of Ordnance Survey. Nor can any contract be formed on Ordnance Survey's behalf via email. We reserve the right to monitor emails and attachments without prior notice.

Thank you for your cooperation.

Ordnance Survey
Romsey Road
Southampton SO16 4GU
Tel: 08456 050505
http://www.ordnancesurvey.co.uk

Received on Tuesday, 15 April 2008 10:18:43 GMT

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