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GeoNames and Spatial Queries

From: Christopher St John <ckstjohn@gmail.com>
Date: Tue, 24 Feb 2009 10:30:58 -0600
Message-ID: <8ba906450902240830u51278a4ey74a3c44566236@mail.gmail.com>
To: public-lod@w3.org
I'm looking for feedback/pointers on best practices
for finding objects in the Linked Data cloud given
a geographic area of interest.

Tom Heath's excellent Linked Data tutorial in Austin
last week inspired me to do a quick Linked
Data-based iPhone application. Think
DBpediaMobile[1], only with a very different user
interface.

I spent some time researching the topic, but I was
having a hard time figuring out what the general
consensus was (or if there was one yet) I'd be happy
to summarize responses into a FAQ answer.

The DBpediaMobile paper[2] says:

 "The map view is built from RDF triples
 obtained by sending the currently visible area
 ... to the server, where they are rewritten as
 a SPARQL query and issued to a Virtuoso server
 that hosts DBpedia’s geocoordinates..."

DBpediaMobile uses GeoNames data, and geonames has
an API with a query called "findNearby" that looks
promising, but I'm assuming that's "cheating".
Calling out to an API breaks the idea of linking
within the data, and means that you can't browse
through without special integration code.

There are proposed extensions to SPARQL to handle
spatial semantics[3]. I suspect that would solve the
"cheating" issue (because the query would presumably
be generic enough to work with any possible data
source), but GeoNames doesn't appear to handle any
SPARQL at all. (I think)

But the excerpt form the paper indicates that the
public GeoNames database is not being used. Instead
the data has been loaded into a private datastore,
presumably one that supports special spatial SPARQL
queries?

Is that the case? I can always just load up whatever
data I need into PostgreSQL (which has excellent
geodata support) and drop down into SQL queries, but
that seems against the spirit of the thing. And of
course at that point it's not really Linked Data at
all because it's not on the web, or shared, or RDF.

Feedback/hints/obvious-things-I-missed/
corrections-to-misapprehensions greatly appreciated.


-cks


[1] http://wiki.dbpedia.org/DBpediaMobile
actually seems to work pretty well on an iPhone,
but there's no GPS info and i'd like to see a
native app instead of something running in the
browser. And what I have in mind has a totally
different UI.

[2] http://beckr.org/wp-content/uploads/DBpediaMobile.pdf

[3] http://data.semanticweb.org/workshop/terra_cognita/2008/paper/main/1/html


-- 
Christopher St. John
http://praxisbridge.com
Received on Tuesday, 24 February 2009 16:31:39 UTC

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