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WCS slicing gives TypeError (used to work)

See original GitHub issue

@mcara wrote some WCS manipulation codes for me that used to work but are now broken with the latest dev version. Relevant snippets below.

# Shrink the image
data = zoom(data, zoom_factor)

# Adjust WCS

slice_factor = 1 / zoom_factor
old_wcs = wcs.WCS(hdr)  # To account for distortion, add "pf" as 2nd arg

# Supress RuntimeWarning about ignoring cdelt because cd is present.
with warnings.catch_warnings():
    warnings.simplefilter('ignore', RuntimeWarning)
    # Update if cropping
    new_wcs = old_wcs.slice((np.s_[::slice_factor], np.s_[::slice_factor]))

Traceback (most recent call last):
...
  File ".../stginga/utils.py", line 349, in scale_image
    (np.s_[::slice_factor], np.s_[::slice_factor]))
  File ".../astropy-1.3.dev16480-py3.5-linux-x86_64.egg/astropy/wcs/wcs.py", line 2983, in slice
    nitems = len(builtins.range(self._naxis[wcs_index])[iview])
TypeError: slice indices must be integers or None or have an __index__ method

How do I make it work again?

Issue Analytics

State:
Created 7 years ago
Comments:10 (10 by maintainers)

Top GitHub Comments

1reaction

MSeifert04commented, Nov 29, 2016

How do I make it work again?

Convince @nden and @astrofrog that #5455 should be merged. 😄

0reactions

MSeifert04commented, Nov 29, 2016

I think #5455 should be merged (not necessarily as-is) just to remain backwards-compatible, so better to discuss this in #5461?

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