Your mobile Topographer! Increase GPS accuracy using: Weighted averaging Map calibration. Device calibration on map, or on a know point. Display and convert GPS geodetic to Cartesian EN coordinates and back: UTM. Europe ETRS89/UTMZ28-38. Hellas Geodetic Reference System HGRS 87 Hellas HTRS07/TM07. Iceland ISN93 / Lambert 93.