This program is designed to match up items in two different lists, which may have two different systems of coordinates. The program allows the two sets of coordinates to be related by a linear, quadratic, or cubic transformation. It is an implementation of the algorithm described in Valdes et al., Publications of the Astronomical Society of the Pacific, vol 107, page 1119 (1995). The program was designed and written to work on lists of stars and other astronomical objects, but it might be applied to other types of data. In order to match two lists of N points, the main algorithm calls for O(N^6) operations (yes, that's N-to-the-sixth), so it's not the most efficient choice. I find myself becoming impatient for N >= 100, but your mileage may vary. On the other hand, it does allow for arbitrary translation, rotation, and scaling... WWW: http://spiff.rit.edu/match/