[foaf-dev] SPARQL GEO and SQL GIS extensions

Dan Brickley danbri at danbri.org
Mon Jan 28 19:26:59 GMT 2008

(switched the subject line, now we're talking tech)

Paul Scott wrote:

>> Talking of cool projects, and getting offtopic for this thread, I see 
>> you have some PHP/PostGIS work,
>> http://gforge2.uwc.ac.za/projects/postgis/ ... I was wondering if you or 
>> others had ever looked into possibility of integrating this with SPARQL 
>> for querying. 
> Sounds tempting...
>> I asked Richard Cyganiak about this recently, eg. idea of 
>> taking D2RQ, and improving it to have knowledge of POSTGIS SQL 
>> extensions. D2RQ can rewrite SPARQL queries into SQL, so I was wondering 
>> if things like http://www.ordnancesurvey.co.uk/oswebsite/ontology/ and 
>> http://www.w3.org/2005/Incubator/geo/
>> http://www.w3.org/2005/Incubator/geo/XGR-geo-20071023/
>> http://www.w3.org/2005/Incubator/geo/XGR-geo-ont-20071023/ ... could 
>> benefit from this as an implementation technique? Any thoughts? Am just 
>> thinking out of loud here. 
> Well, it so happens that the other day I was thinking about exactly
> this, so I sat down and wrote a GeoRSS module for the Chisimba Framework
> http://avoir.uwc.ac.za/avoir/index.php?module=cms&action=viewsection&id=gen12Srv48Nme23_82
>  (which I wrote a FOAF module as well as the start of a Semantic Campus
> add-on for as well).

Oh, nice :) Is the FOAF module online somewhere? I had search/browse 
around but couldn't find it yet.

  The next step I thought would be to munge the
> geoRSS generated points, polygons and linestrings into meaningful FOAF
> triples as well all for context.

I forgot one more link. Leigh Dodds (cc:'d) had some Jena extension code 
for such queries. Unfortunately he lost a domain name, so the files are 
currently only in archive.org links:


(Leigh - any luck fixing the domain name? not sure if archive.org has 
all your stuff)

> This is certainly an avenue that I would like to explore further, as
> soon as I have some time that is (I only get to hack around with
> geography and SW in my spare time unfortunately).

I've always thought geo and semweb a particularly good pairing, since SW 
thrives on cross-domain, and geographic restriction is one way of 
narrowing down application focus (eg. to a city, region etc) while 
keeping the cross-domain information mixing that semweb does so well. I 
hope you find some hacking time :)

> It would be great to get in touch with some others that may be
> interested and see what we can come up with.

Likewise. I've not much hands-on experience with D2RQ nor the GIS 
extensions to Postgres or MySQL yet. But if I can find a way to help I'd 
be happy to!



> Thanks for the links, that looks like a pretty decent starting point at
> least!

ps. http://esw.w3.org/topic/GeoInfo might be a handy place to keep 
collaborative notes, although it looks like it needs an update. GeoURL 
is long gone...

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