I have two versions of data from the same set of points, however the points are not aligned with one another using the same projection system for both. I have determined one set of data to be "correct" in the expected coordinate system. I believe the problem is that the "errant" data results from the mishandling of the projection system. Is it possible to take the two sets of x/y's and the correct projection system and determine what projection system must have been mistakenly used? If this can be determined, I might be able to re-project the errant data so that it aligns with what I believe to be the "correct" data.