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.
There was a major change in version 0.15: the first stage uses the clever method
of finding the most likely triangles described in Tabur, Publications of the
Astronomical Society of Australia, vol 24 , page 189 (2007). This replaces the
more brute-force-ish method of Valdes et al., Publications of the Astronomical
Society of the Pacific, vol 107, page 1119 (1995), which was employed in version
up to 0.14.

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/