Are there any software programs that allow you to import an equirectangular projection and manually play with the distortion on it? I have an "almost" equirectangular map that is the result of a lot of work using unorthodoxed methods, going from 3d to 2d using a 3d scanner. The final process has resulted in an equirectangular projection that is 12 degrees off in distortion at the poles (they are too large), resulting in something between a mercator projection and an equirectangular projection(and I don't mean quantitatively). I'm looking to fix this by adjusting the distortion and making this a true equirectangular projection, the final result doesn't have to be exact, just close enough.

Any help locating software that can do this and any pointers are welcome!

Thanks!