I can recommend the excellent Geographic lib::Geodesic for this having used it in the past. http://geographiclib.sourceforge.net http://geographiclib.sourcefor

I can recommend the excellent Geographic lib::Geodesic for this having used it in the past. http://geographiclib.sourceforge.net http://geographiclib.sourceforge.net There is a python implementation available as well. http://pypi.python.org/pypi/geographiclib http://pypi.python.org/pypi/geographiclib