Er, rather, select st_asbinary(st_extent(geom)), st_zmin(geom), st_zmax(geom) from gtable;
? elegance, we don't need no stinking elegance... P On Mon, Jan 11, 2010 at 10:35 AM, Paul Ramsey <[email protected]> wrote: > Just spitballing, since you have to work with what's there, perhaps do > a st_extent to get x/y then do a second pass getting zmin and zmax? > > P > > On Mon, Jan 11, 2010 at 8:38 AM, Abram Gillespie > <[email protected]> wrote: >> OK, I'll ask this then. What's the best way to get this: >> >> select ST_Extent3d(geometry_column) from my_table; >> >> Into EWKB w/o losing the Z (or M) coordinate? >> >> Doing: >> >> select ST_AsEWKB(ST_Extent3D(geometry_column)) from my_table; >> >> unfortunately falls prey to the issue we're discussing. >> >> Thanks. >> -Abe >> >> On Sun, Jan 10, 2010 at 10:53 PM, Paragon Corporation <[email protected]> wrote: >>> As a side note. ST_Zmax doesn't exist for geometries. It works because >>> geometries can be autocast to boxes. >>> >>> See matrix >>> http://www.postgis.org/documentation/manual-svn/ch08.html#PostGIS_TypeFuncti >>> onMatrix >>> >>> -----Original Message----- >>> From: [email protected] >>> [mailto:[email protected]] On Behalf Of Paragon >>> Corporation >>> Sent: Sunday, January 10, 2010 10:50 PM >>> To: 'PostGIS Users Discussion' >>> Subject: Re: [postgis-users] Bug dropping the Z coordinate? >>> >>> Abe, >>> >>> It seems we are flattening the box3d geometry in to a 2D polygon always >>> instead of as a 3D/2.5D polygon. >>> I'm not sure it's a bug though, because I think a box3d is an invalid 2.5/3D >>> polygon if you were to construct it. >>> >>> Can you envision it? >>> >>> Paul, Mark or Kevin might have a better clue, but I think it's at best an >>> ambiguous 3D polygon and that is the problem. A box3d isn't really a 3D box, >>> its more just a coordinate bounding thing. >>> >>> Hope that helps, >>> Regina >>> >>> -----Original Message----- >>> From: [email protected] >>> [mailto:[email protected]] On Behalf Of Abram >>> Gillespie >>> Sent: Sunday, January 10, 2010 4:31 PM >>> To: PostGIS Users Discussion >>> Subject: [postgis-users] Bug dropping the Z coordinate? >>> >>> Is this a bug? >>> >>> select ST_ZMax('BOX3D(0 0 0,0 0 1)'::box3d); >>> >>> versus >>> >>> select ST_ZMax(ST_GeomFromEWKB(ST_AsEWKB('BOX3D(0 0 0,0 0 1)'::box3d))); >>> >>> The first query returns "1" as expected but the second returns "0" as >>> unexpected. >>> >>> I'm trying to add Z/M support to zigGIS and this is show-stopping me. >>> Any work-arounds if this is a bug? Also, I'll be happy to report the bug if >>> so. >>> >>> Thanks. >>> -Abe >>> _______________________________________________ >>> 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 >>> >>> >>> _______________________________________________ >>> 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 >> > _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
