Turns out this is just because the definition of 23030 has been updated to include a to_wgs84 parameter. You get the same behavior in any version of proj. This is a feature, not a bug (our projection information is now better). If you want the old behaviour, change the proj4text of 23030 back to the 1.5 version.
For a future release you might file a ticket to allow users to apply transforms x/y but to skip the z-coordinate. P. On Fri, Mar 30, 2012 at 10:27 AM, Paul Ramsey <pram...@opengeo.org> wrote: > Yeah, bad news, 2.0 is showing this behavour but not 1.5. > > http://trac.osgeo.org/postgis/ticket/1742 > > P. > > On Fri, Mar 30, 2012 at 9:59 AM, Stefano Iacovella > <stefano.iacove...@gmail.com> wrote: >> Hi Jose >> >> Im sure which version of PostGis are you using. >> On my box, Postgis 1.5.3 with Proj 4.8 it seems to work without any >> change to elevation: >> >> template_postgis=# select >> st_asewkt(st_transform(st_geomfromtext('POINT (700000 4500000 100)', >> 23030), 4326)); >> WARNING: OGC WKT expected, EWKT provided - use GeomFromEWKT() for this >> st_asewkt >> ---------------------------------------------------------- >> SRID=4326;POINT(-0.635451186670006 40.6259397158234 100) >> (1 row) >> >> >> template_postgis=# select postgis_full_version(); >> postgis_full_version >> >> -------------------------------------------------------------------------------- >> ------------------ >> POSTGIS="1.5.3" GEOS="3.3.2-CAPI-1.7.2" PROJ="Rel. 4.8.0, 6 March 2012" >> LIBXML= >> "2.7.6" USE_STATS >> (1 row) >> >> >> Regards >> >> Stefano >> >> 2012/3/30 Jose Carlos Martinez <jomar...@cgf.upv.es>: >>> I didnt get nay answers from now. >>> Someone can tell me why postgis is changing the z coordinate and how i can >>> change this default behavior? >>> Should I keep using proj4.7 instead of proj4.8? >>> >>> >>> Before: >>> pg20=# select st_astext(st_transform(st_geomfromtext('POINT (700000 4500000 >>> 100)', 23030), 4326)); >>> st_astext >>> -------------------------------------------------------------- >>> POINT Z (-0.63662073736203 40.6248036513963 100) >>> >>> >>> Now: >>> pg20=# select st_astext(st_transform(st_geomfromtext('POINT (700000 4500000 >>> 100)', 23030), 4326)); >>> st_astext >>> -------------------------------------------------------------- >>> POINT Z (-0.63662073736203 40.6248036513963 168.35361468256) >>> >>> >>> >>> On 27/03/2012 21:56, Jose Carlos Martinez Llario wrote: >>>> >>>> From proj4.8 changelog: >>>> >>>> "Preliminary support has been added for vertical datums using the >>>> +geoidgrids= directive. The geoidgrids are assumed to provide a >>>> transformation from geoid elevations to ellipsoidal elevations and they are >>>> discussed a bit in the VerticalDatums topic on the web site" >>>> >>>> I dont like the st_transform method can change my z coordinates by default >>>> though, dont know if it is because PostGIS is not ready still for proj4.8 >>>> or >>>> because it is the proj4.8 default behaviour. >>>> >>>> cheers, >>>> Jose >>>> >>>> >>>> On 27/03/2012 19:02, Jose Carlos Martinez wrote: >>>>> >>>>> Hi, dont know if this is the expected behavior, maybe its because I built >>>>> postgis with proj 4.8 or because something has changed in spatial_ref_sys. >>>>> Dont know at what time it happened (I missed it). >>>>> >>>>> Before: >>>>> pg20=# select st_astext(st_transform(st_geomfromtext('POINT (700000 >>>>> 4500000 100)', 23030), 4326)); >>>>> st_astext >>>>> -------------------------------------------------------------- >>>>> POINT Z (-0.63662073736203 40.6248036513963 100) >>>>> >>>>> >>>>> Now: >>>>> pg20=# select st_astext(st_transform(st_geomfromtext('POINT (700000 >>>>> 4500000 100)', 23030), 4326)); >>>>> st_astext >>>>> -------------------------------------------------------------- >>>>> POINT Z (-0.63662073736203 40.6248036513963 168.35361468256) >>>>> >>>>> Using ST_AsKml Its changing the Z coordinate too. >>>>> >>>>> Someone can confirm when this change happened in PostGIS? >>>>> >>>>> Regards, >>>>> Jose >>>>> >>>>> >>>>> _______________________________________________ >>>>> postgis-users mailing list >>>>> postgis-users@postgis.refractions.net >>>>> http://postgis.refractions.net/mailman/listinfo/postgis-users >>>> >>>> >>> >>> _______________________________________________ >>> postgis-users mailing list >>> postgis-users@postgis.refractions.net >>> http://postgis.refractions.net/mailman/listinfo/postgis-users >> _______________________________________________ >> postgis-users mailing list >> postgis-users@postgis.refractions.net >> http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
