Charlie, That is kind of weird. Although
select 'srid=4326;point(3 3)'::geometry union all select 'srid=4325;point(3 3)'::geometry Works as you would expect since it never has to do any compare between geometries. 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. So I would say this is a limitation of design rather than a bug. Thanks, Regina -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Charlie Savage Sent: Saturday, September 27, 2008 4:34 PM To: PostGIS Users Discussion Subject: Re: [postgis-users] Comparing Geometries with Different SRIDs This looks like a related issue: select 'srid=4326;point(3 3)'::geometry union select 'srid=4325;point(3 3)'::geometry ERROR: Operation on two GEOMETRIES with different SRIDs I find that surprising, I would expect to get a result table with two rows. Charlie Charlie Savage wrote: > Here is another SRID issue that seems strange: > > select 'srid=4326;polygon((0 0, 0 5, 5 5, 5 0, 0 0))'::geometry = > 'point(2 2)'::geometry > > > ERROR: Operation on two GEOMETRIES with different SRIDs > > > Why not just return FALSE? I can see forcing the same SRID when > performing operations such as unions, but if the geometries have > different SRID's then it seems reasonable to assume they are not > equivalent. > > > Charlie > > > ---------------------------------------------------------------------- > -- > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users -- Charlie Savage http://cfis.savagexi.com _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
