- From: John Goodwin <John.Goodwin@ordnancesurvey.co.uk>
- Date: Wed, 25 Feb 2009 09:06:56 -0000
- To: <public-lod@w3.org>
Christopher St John wrote: > I'm looking for feedback/pointers on best practices for > finding objects in the Linked Data cloud given a geographic > area of interest. Currently the only mainstream RDF triplestore I am aware of that does efficient spatial indexing is Allegrograph (http://agraph.franz.com/). Of course this would involve loading your spatial RDF into a local triple store. Personally I would like to see the spatial datatypes provided as part of the GML spec (http://en.wikipedia.org/wiki/Geography_Markup_Language) put on an equal footing as other XML datatypes which would at least provide a standard (along with the work done here http://www.w3.org/2005/Incubator/geo/) on which tool developers could build. This would all SPARQL queries like select ?s ?o where { ?s hasGeom ?g1 ?o hasGeom ?g2 FILTER (TOUCH(?g1,?g2)= true) } However, I don't think the problem of spatial indexing over the linked data web is going to be solved any time soon. We (at OS) think a lot of traction can be gained from developing gazetteers in RDF with topological relationships between geographic regions (http://www.ordnancesurvey.co.uk/oswebsite/ontology/ http://os.rkbexplorer.com/) (Dbpedia, geonames and freebase all do similar things as well). At least then you can ask queries like "find me all pubs in England", "Find me hotels in Hampshire and cities bordering Hampshire" without the need for geometries or spatial indexing. Not sure if that answers your question... John . 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. Ordnance Survey Romsey Road Southampton SO16 4GU Tel: 08456 050505 http://www.ordnancesurvey.co.uk
Received on Wednesday, 25 February 2009 09:07:33 UTC