Dear list, I am trying to compare 2 different projections using OSR in Python. One SRS is initialized from a proj4 string given by PostGIS. It's a custom definition, so using EPSG is unfortunately not an option.
The other SRS is read from a Geotiff raster using GDAL, so initialized via Wkt from ds.GetProjection(). My method of comparing is maybe a bit naive, i tried: srs1.ExportToProj4() == srs2.ExportToProj4() If there something better i'd be happy to hear. The problem is however that both ExportToWkt() statements return a different string. The one initialized from Wkt defines the datum as "+datum=WGS84", which is identical to running "gdalinfo -proj4" and i assume this is correct. The other srs changes this to "+ellps=WGS84 +towgs84=0,0,0,0,0,0,0". Here is a notebook replicating the behavior, but without using a raster: https://gist.github.com/RutgerK/e4e40b1025f7279af430 Why is the ExportToProj4() different then the string from which it was initialized? A workaround for me would be to first read the Wkt from the raster and initialize a srs-object, export from that object to proj4 and use that to initialize a new srs-object and go from there. That doesn't seem right though, so would be happy if someone can point me in the right direction. Regards, Rutger -- View this message in context: http://osgeo-org.1560.x6.nabble.com/Comparing-two-SRS-s-different-Proj4-tp5255792.html Sent from the GDAL - Dev mailing list archive at Nabble.com. _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
