Am 17.09.2015 um 05:54 schrieb Andre Joost: Meanwhile I did some research, this is what I understand:
> No, both WKT definition and proj.4 definition are not capable of > defining the transition from ellipsoid to spheroid in the way Google > uses it. Proj4 can: "+nadgrids=@null" is hackish, but I think it does the right thing using a current Proj4. This is what makes the WKT with Proj4 extension working. WKT without Proj4-String also can, but you have to give an applicable PROJECTION parameter, and the software has to implement it. From what I found on the net, ESRI named their method "Mercator_Auxiliary_Sphere". GDAL seems to provide no matching method, but not sure about this. epsg-registry.org now provides WKT strings following the current WKT standard <http://docs.opengeospatial.org/is/12-063r5/12-063r5.html>. It uses 'CONVERSION["Popular Visualisation Pseudo-Mercator", METHOD["Popular Visualisation Pseudo Mercator",ID["EPSG",1024]]'. This form of WKT is a very recent standard, I don't know which software currently has support for it. "Operation Method" EPSG 1024 is a textual description with formulas, how the conversion has to be done. It can be implemented independent of WKT version. Redoute _______________________________________________ Qgis-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-user
