These routines compute the transverse Mercator projection by means of a novel Fourier-based technique, which is much more efficient than conventional methods based on the evaluation of power series if you want to project a large number of points (say 32 or more along a meridian). The method is described in a paper, "Efficient computation of the transverse Mercator projection", which is currently being refereed. The paper is not available on-line. I haven't tried to optimize this code to the fullest extent. In particular, in places, trivial multiplications are avoided by a run- time test to see if either operand is 0 or 1. This is not cheating (although it looks like it), because in each case the fact that the multiplication is trivial is known "a priori", independently of the data, and a "proper" implementation would make the appropriate optimizations. So the operation counts reported by the program, and documented in the paper, really are realistic and accurate. Honestly! A.J. Fisher