Repository navigation
Pyregion should use distortion-aware WCS functions for coordinate transformations #35
Description
Currently, pyregion uses WCS functions that do not take into account distortion corrections: wcs.wcs_world2pix() and wcs.wcs_pix2world(). However, distortions for most HST instruments are significant and should be taken into account. This could be done by switching to wcs.all_world2pix() and wcs.all_pix2world() - really a very simple change to the code.
While at this moment I cannot recommend this change until issues in astropy/astropy#1977, scipy/scipy#3227, astropy/astropy#2294 are solved. I have submitted a PR that fixes these issues in all_world2pix() and provides performance improvements astropy/astropy#2373 but it is not yet merged.
I will post here when it is safe to do this transition.
NOTE: for images that do not have distortions wcs.all_world2pix() and wcs.all_pix2world() are similar to their -non-distortion-aware analogs wcs.wcs_world2pix() and wcs.wcs_pix2world().
Activity
Obliterate Kapteyn code. Leave no survivors.
Obliterate Kapteyn code. Leave no survivors.
Obliterate Kapteyn code. Leave no survivors.
cdeil commentedon Aug 1, 2016
@mcara - Thanks for filing this issue.
All of the issues you linked to are now closed or merged.
Maybe, as a start, @mcara , you could post a test case example here, or contribute it directly as a test via a pull request?
Such a concrete example could be useful, so that everyone can run it through DS9 and pyregion and then participate in the discussion whether the change you're proposing should be made.
Obliterate Kapteyn code. Leave no survivors.
mcara commentedon Aug 10, 2016
@cdeil Please review my PR #97
Obliterate Kapteyn code. Leave no survivors.
Obliterate Kapteyn code. Leave no survivors.