| Hi, How do I specify a nearest neighbour query using wms spatial filters (or CQL) ? or is this possible in Geoserver ? if it is, what postgis function is used in this operation ? thanks, Roman |
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Roman Isitua ha scritto:
Hi,
How do I specify a nearest neighbour query using wms spatial filters (or CQL) ? or is this possible in Geoserver ? if it is, what postgis function is used in this operation ?
No, there is no such a function, and afaik PostGIS does not have
a nearest neighbour function either.
Some time ago a user contributed a a WFS extension that
did exactly that, added a WFS method called GetNearest.
Unfortunately the extension has not been maintained and has
never been shipped along with GeoServer.
Anyways, you can still find it here:
http://svn.codehaus.org/geoserver/branches/1.6.x/geoserver/community/WFSGetNearest/
For the future, this kind of operation should be implemented
as a WPS call, since it's actually processing, but don't hold
your breath on it, month may pass before we have a usable WPS
service
Cheers
Andrea
--
Andrea Aime
OpenGeo - http://opengeo.org
Expert service straight from the developers.