----------------------------Original message---------------------------- To Judy Geitgey - I saw your inquiry on maps-L about information to convert earth-centered coordinates to transverse mercator and offer the following information for your patron. If your library doesn't have these works, we could loan them to you through Inter-library loan (our OCLC code is GEM). Snyder, John P., Map Projections-- A Working Manual, 1987, USGS Professional Paper 1395, 383 p. Snyder, John P., Computer-Assisted Map Projection Research, 1985, USGS Bulletin 1629, 157 p. Hope this helps. Mary E. (Betty) Graziani USGS NMD Reference Collection 522 National Center Reston, VA 22092 [log in to unmask]