Dear Colleagues: I've written up the geodesic algorithms used in GeographicLib. For a preprint see: http://arxiv.org/abs/1102.1215 Comments are welcome! -- Charles Karney <charles.karney at sri.com> SRI International, Princeton, NJ 08543-5300 Tel: +1 609 734 2312 Fax: +1 609 734 2662