Hi Alex
Alexander Dutton wrote:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hi all,
We've currently got a lot of (simple) geospatial data in
<http://data.clarosnet.org/> (served behind the scenes by Fuseki).
We'd like to do some geospatial indexing magic, and were wondering
about writing something a bit like LARQ that will pull out things like
geo:Points and WKT literals, place them in a PostGIS-flavoured DB, and
then implements something like GeoSPARQL (<http://geosparql.org/>).
Which kind of queries you would like/need to run?
The use cases I've seen (on the job) are often quite simple, since users
are not GIS expert. The vast majority of them can be reduced to:
- searching near by a point (often sorting results by distance)
- searching within a bounded box
Ideally, it would be good to have something pure Java which keeps
things very simple to install. Ideally, zero installation cost:
download, unzip, load data, run (as it is for Fuseki).
What would be the best way to integrate|use such extensions into Fuseki?
Ideally, with 0 changes to Fuseki code base... is that currently possible?
Also, I have not been following the progress around GeoSPARQL:
http://www.opengeospatial.org/projects/groups/geosparqlswg
... is there anything interesting/relevant there? Code? :-)
Finally, things to think about are:
- how to you initially build your geo indexes?
- how you keep those indexes up-to-date as you add/remove triples|quads?
- how do we plug-in|use|integrate this from|into ARQ (or TDB or Fuseki)?
Currently, I am not completely satisfied by how we|I do this with LARQ
(via assemblers), but maybe it's just because I am not an Jena's assembler
guru.
Ideally, I'd like to have a way to add property functions to ARQ (and use
them with TDB datasets or Fuseki) without changing ARQ or TDB nor Fuseki
source code. You drop a jar in your class path and the property function
as well as keeping indexes up-to-date is there.
Paolo
Has anyone started doing this or something similar? I'm happy to give
it a go and I'm sure my employer would be happy to contribute it back
to Jena and the ASF. My plan was to go through the LARQ codebase to
work out how it hooks itself in, and use that as a model.
Yours,
Alex
- --
Alexander Dutton
Metamorphoses Project Developer, Claros
Oxford University Computing Services, ℡ 01865 (6)13483
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)
Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/
iEYEARECAAYFAk5vQbgACgkQS0pRIabRbjC9QACfTZtTcFIhDXjWPR+MpEWunKkt
38oAnR5n+oi1nuTZAfRdOrF2mcOac2Ck
=r1dj
-----END PGP SIGNATURE-----
