I've written up my implementations of the transverse Mercator projection from GeographicLib. For a preprint see: http://arxiv.org/abs/1002.1417 Comments welcome! --Charles -- Charles Karney <ckarney at sarnoff.com> Sarnoff Corporation, Princeton, NJ 08543-5300 Tel: +1 609 734 2312 Fax: +1 609 734 2662