Right, I tried it without the Bursa Wolf parameters, and indeed the results are near identical:
epsg-wkt: 278204.21690185793, 187591.0788272909 PostGIS: 278204.250150917 187591.006280736 As opposed to epsg-hsql: 278291.1032887026, 187619.97719849477 So your hypothesis is correct. Digging into the PROJ.4 docs, it says: "Support has also been added for 3 and 7 parameter datum shifts" but various mailing list posts imply that PostGIS maybe doesn't always take advantage, eg: "The most common reason for failure to populate a datum shift is that there are more than one available going to WGS84 for a given datum. Since I can't know which is best, I just ignore them all." - http://postgis.refractions.net/pipermail/postgis-users/2005-October/009678.html). As a novice, I am struggling to understand the details, so suffice to say that GeoTools is accurate and (my Windows installation of) PostGIS/PROJ.4 is not! Thanks again. Simon ------------------------------------------------------- This SF.Net email is sponsored by the JBoss Inc. Get Certified Today * Register for a JBoss Training Course Free Certification Exam for All Training Attendees Through End of 2005 Visit http://www.jboss.com/services/certification for more information _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
