> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Charlie Savage > Sent: Saturday, September 27, 2008 2:31 PM > To: PostGIS Users Discussion > Subject: Re: [postgis-users] Comparing Geometries with Different SRIDs > > > > > > > > I guess its because at some point to determine uniqueness > UNION has to > > call something like ST_Equals and since all the PostGIS relation > > functions are only supported for geometries with the same SRID it > > would fail. > > Look like it: > > select st_equals('srid=4326;point(3 3)'::geometry, > 'srid=4325;point(3 3)'::geometry) > > ERROR: Operation on mixed SRID geometries > > > > So I would say this is a limitation of design rather than a bug. > > I disagree. I think ST_EQUALS should return false here, not blow up.
The 2 point could be spatially equal given different SRIDS and coordinates if they were projected to a common SRID. So should geometry operators silently Call st_transform to make the righthand match the lefthand before comparing? This would be quite the expensive operation. > > Charlie > _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
