IRAF geomap and geotran routines for detector-to-sky geometric distortion mapping

Carlos Roman 3 years ago • updated 3 years ago 3

Some elegant way to produce a WCS from an image, given a list of pixel positions and a matched list of sky positions would be very nice.

A simple version, ignoring the distortion between focal plane and detector plane, could be hand rolled by the user following the steps outlined here once the Scale and Shift models in astropy become fittable; there is a pull request for that here.

For context: the IRAF geomap/geotran tasks are used to generate distortion maps *and* do the "undistorting".

In the current astropy ecosystem the former task might be taken up by (non-existent) tools that generate astropy.wcs or gwcs representations. Then other tools like reproject could use that to do the image distortion itself. That makes it easier to mix-and-match different needs for different science cases.

Thank you Erik. I am an IDL+IRAF person and just recently started using astropy more frequently. Your reccomendation sounds like the right thing to do.