Dear Gavin, the problem is probably the difference of the datum shift parameters between PostGIS and GeoServer transformations.
if this is the case, then look at this: http://docs.geoserver.org/stable/en/user/advanced/crshandling/customcrs.html you can override the built-in epsg parameters in Geoserver by creating the epsg_overrides.properties file, and placing the WKT form of the PostGIS parameters. Read carefully the instructions, you will also have to remove the "authority" information as it says. I hope it will help. GEDE Mátyás ELTE Térképtudományi és Geoinformatikai Tanszék, Budapest On Fri, 15 Feb 2013 17:58:20 +0200, Gavin Fleming wrote > In trying to troubleshoot why the same data as a geoserver wms and > postgis vector were shifted relative to one another, I picked up > that they are projecting differently (26331 to 3875): > > input point example: > > "SRID=26331;POINT(542053.551 787930.307)" > > in postgis (2.0): > > "SRID=3857;POINT(376265.240380565 795675.534596811)" > > in geoserver (2.2-SNAPSHOT): > > "SRID=3857;POINT(376271.1415793335 790368.2841989407)" > > proj4 text that postgis uses: > > +proj=utm +zone=31 +ellps=clrk80 +towgs84=-92,-93,122,0,0,0,0 > +units=m +no_defs > > The WKT parameters that geoserver users: > > I can't find them...I tried to follow these instructions > http://docs.geoserver.org/latest/en/user/advanced/crshandling/manualepsg.html but they appear to be out of date since instead of EPSG.sql there is now EPSG.zip containing EPSG.script, EPSG.properties and EPSG.data. The latter which probably contains the projection definitions is binary. > > postgis WKT for comparison: > > PROJCS["Minna / UTM zone > 31N",GEOGCS["Minna",DATUM["Minna",SPHEROID["Clarke 1880 > > (RGS)",6378249.145,293.465,AUTHORITY["EPSG","7012"]],TOWGS84[-92,-93, > 122,0,0,0,0], AUTHORITY["EPSG","6263"]],PRIMEM["Greenwich",0, > AUTHORITY["EPSG","8901"]], UNIT["degree",0.0174532925199433, > AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4263"]], UNIT["metre",1, > AUTHORITY["EPSG","9001"]],PROJECTION["Transverse_Mercator"], > PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",3], > PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000], > PARAMETER["false_northing",0],AUTHORITY["EPSG","26331"], > AXIS["Easting", EAST],AXIS["Northing",NORTH]] > > Any ideas which definition or transformation engine might be wrong? > > -- > regards > > Gavin > > Gavin Fleming > http://afrispatial.co.za > t: 0218630660 > c: 0845965680 > f: 0866164820 > > ------------------------------------------------------------------------------ > Free Next-Gen Firewall Hardware Offer > Buy your Sophos next-gen firewall before the end March 2013 > and get the hardware for free! Learn more. > http://p.sf.net/sfu/sophos-d2d-feb > _______________________________________________ > Geoserver-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/geoserver-users GEDE Mátyás ELTE Térképtudományi és Geoinformatikai Tanszék, Budapest ------------------------------------------------------------------------------ Free Next-Gen Firewall Hardware Offer Buy your Sophos next-gen firewall before the end March 2013 and get the hardware for free! Learn more. http://p.sf.net/sfu/sophos-d2d-feb _______________________________________________ Geoserver-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geoserver-users
