The Quadrilateral Warp

A quadrilateral warp is designed to warp one rectangular region into another, typically by entering the old and new locations of the four corners of the region to be warped. This warp can produce highly unstable results for locations outside the four warp points, including caustics and flipped data. It is highly recommended that the extreme corners be used to produce a regular result.  A better result might be obtained using the above Three-point warp method extended to 4 points.