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Re: ESWC 2008 Linked Data Playground

From: Hugh Glaser <hg@ecs.soton.ac.uk>
Date: Fri, 30 May 2008 09:19:16 +0100
To: "public-lod@w3.org" <public-lod@w3.org>
Message-ID: <C4657714.24DC1%hg@ecs.soton.ac.uk>

I'll try :-)
(My SPARQL is pretty rubbish, so this could be embarrassing.)
The simplest query would be:

SELECT ?lat ?long WHERE {
<http://dbpedia.org/property/city> ?city .
?city <http://www.w3.org/2003/01/geo/wgs84_pos#lat> ?lat .
?city <http://www.w3.org/2003/01/geo/wgs84_pos#lat> ?long

You can try pasting this into http://dbpedia.org/sparql

On 30/05/2008 03:19, "David Huynh" <dfhuynh@alum.mit.edu> wrote:

> Hugh Glaser wrote:
>> Hmm.
>> In a linked data world, the location of the institution would be published,
>> and then another linked world would be used to map place to lat/long?
>> This could actually happen just within dbpedia.
>> So looking up the institution in dbpedia will often give the p:city, which
>> leads to geo:lat and geo:long.
>> So what is needed is to sameAs
>> http://data.semanticweb.org/organization/humboldt-universitaet-berlin
>> and
>> http://dbpedia.org/page/Humboldt_University_of_Berlin
Oh dear, sorry, should have been
>> etc
>> And then follow the Linked Data road.
>> There are other solutions, but this is probably the simplest and safest?
> Would someone familiar with how to do that just give me a RDF/XML file
> of the lat/lng coordinates?
Sorry, in my version of the LOD world, this is expressly forbidden.
The RDF is out there, so (because we call this the Semantic *Web*), we have
to use it as links without just bringing it all in house as a copy.
> Or give me some more detailed actions. :-)
Hopefully the SPARQL above is a start.
If you want the RDF, use:
PREFIX sweb: <http://data.semanticweb.org/whatever#>
<http://dbpedia.org/resource/Humboldt_University_of_Berlin> sweb:lat?lat .
<http://dbpedia.org/resource/Humboldt_University_of_Berlin> sweb:long ?long
<http://dbpedia.org/property/city> ?city .
?city <http://www.w3.org/2003/01/geo/wgs84_pos#lat> ?lat .
?city <http://www.w3.org/2003/01/geo/wgs84_pos#lat> ?long
> I'm playing a dumb user here, who has no idea how to "sameAs" URIs. And
> how do I follow the Linked Data road without tedious handling of URIs?
Excellent; please keep trying, it is a great question.
The owl:sameAs is what you need in your store, as that is what will make the
link from your store to dbpedia (or you could have used the dbpedia URIs in
the first place).
But I'm afraid you need to use URIs if you want to follow our little road.
So those queries, or whatever, are what you use in your application to get
to the lat & long, given a URI like
http://data.semanticweb.org/organization/humboldt-universitaet-berlin that
you know is the same as

> I think this is a rather realistic and conceptually simple task--getting
> related data given some existing data--that LOD would be wonderful for.
> Please show me the way!
> David
Received on Friday, 30 May 2008 08:20:10 UTC

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