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RE: Spatial datatypes and RDF/OWL

From: John Goodwin <John.Goodwin@ordnancesurvey.co.uk>
Date: Mon, 14 Apr 2008 11:43:38 +0100
Message-ID: <6A035FEF345E064E893D784097F8BC7F02434326@OSMAIL.ordsvy.gov.uk>
To: "Steve Harris" <swh@ecs.soton.ac.uk>
Cc: <semantic-web@w3.org>

Hi Steve,

Thanks for your reply. It would be nice to generalise this to other
spatial datatypes like lines and polygons - but certainly would be
non-trivial I'm sure. 

Has much work been done on spatial indexing of RDF?

John

-----Original Message-----
From: Steve Harris [mailto:swh@ecs.soton.ac.uk] 
Sent: 14 April 2008 11:39
To: John Goodwin
Cc: semantic-web@w3.org
Subject: Re: Spatial datatypes and RDF/OWL

Hi John,

Sure, that's how people use geo:lat and geo:log now, eg.

   <geo:Point>
     <geo:lat>55.701</geo:lat>
     <geo:long>12.552</geo:long>
   </geo:Point>

and then query on the bNode of the Point.

It requires a fair amount of smarts in the RDF engine's index, and/or  
the FILTER function, but it's a well understood problem.

- Steve

On 14 Apr 2008, at 11:12, John Goodwin wrote:
> 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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>

.


This email is only intended for the person to whom it is addressed and may contain confidential information. If you have received this email in error, please notify the sender and delete this email which must not be copied, distributed or disclosed to any other person.

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.

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Southampton SO16 4GU
Tel: 08456 050505
http://www.ordnancesurvey.co.uk

Received on Monday, 14 April 2008 10:44:19 UTC

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