Hi Thomas, Thanks. Should I compile this to an exe or an other type of file? Where should I put that file in order to use it in QGIS? Regards, Jochem -- View this message in context: http://osgeo-org.1560.x6.nabble.com/towgs84-approximation-error-tp5313738p5313769.html Sent from the PROJ.4 mailing list archive at Nabble.com.