Validation and Bounds checking

Validating the WCS keywords in a FITS file

astropy includes a command-line tool, wcslint, to check the WCS keywords in a FITS file. The example below shows it reporting back results for a problematic file named invalid.fits:

> wcslint invalid.fits
HDU 1:
  WCS key ' ':
    - RADECSYS= 'ICRS ' / Astrometric system
      RADECSYS is non-standard, use RADESYSa.
    - The WCS transformation has more axes (2) than the image it is
      associated with (0)
    - 'celfix' made the change 'PV1_5 : Unrecognized coordinate
      transformation parameter'.

HDU 2:
  WCS key ' ':
    - The WCS transformation has more axes (3) than the image it is
      associated with (0)
    - 'celfix' made the change 'In CUNIT2 : Mismatched units type
      'length': have 'Hz', want 'm''.
    - 'unitfix' made the change 'Changed units: 'HZ      ' -> 'Hz''.

Bounds checking

Bounds checking is enabled by default, and any computed world coordinates outside of [-180°, 180°] for longitude and [-90°, 90°] in latitude are marked as invalid. To disable this behavior, use astropy.wcs.Wcsprm.bounds_check.