Hi Regina Thanks for the help.
I don't understand " INNER JOIN reference As r ON". I get the error - > relation "reference" does not exist. It doesn't like my substitution for reference either. Bob Bob ----- Original Message ----- From: Paragon Corporation To: 'PostGIS Users Discussion' Sent: Sunday, April 19, 2009 8:58 PM Subject: RE: [postgis-users] Reference Grid Bob, Does the below help any. The below will give you the centroid of the portion of geometries that intersect a reference grid where the grid of the reference is defined by reference.the_geom SELECT r.gid, r.the_geom, ST_Centroid(ST_Collect(ST_Intersection(r.the_geom,p.the_geom))) As the_centroid FROM tblpolygons As p INNER JOIN reference As r ON ST_Intersects(p.the_geom, r.the_geom) GROUP BY r.gid, r.the_geom Hope that helps, Regina ------------------------------------------------------------------------------ From: [email protected] [mailto:[email protected]] On Behalf Of Bob Pawley Sent: Sunday, April 19, 2009 1:58 PM To: PostGIS Users Discussion Subject: [postgis-users] Reference Grid Hi I'm using a reference grid of small polygons. I have been trying to collect concurrent polygons into one geometry in order to establish the centroid of the region covered. I've tried a number of operations such as union, contains, accum etc. I haven't been successful. Can anyone give me some ideas?? Bob ------------------------------------------------------------------------------ _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
_______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
