* @param lon (out) Longitude, in radians
* @param alt (out) Altitude, in meters above the WGS84 ellipsoid
*/
-void sgCartToGeod(double* xyz, double* lat, double* lon, double* alt);
+void sgCartToGeod(const double* xyz, double* lat, double* lon, double* alt);
/**
* Convert a cartesian point to a geodetic lat/lon/altitude.