[AstroPy] Problem running pywcs example

Michael Droettboom mdroe@stsci....
Wed Aug 18 14:04:48 CDT 2010


This problem occurs due to a version incompatibility between pyfits and 
pywcs.

Recent versions of pyfits (2.3 and later) were refactored to no longer 
support numarray.  pywcs required a change to be compatible with this 
(this change first appeared in pywcs 1.8).

Given the versions you list, you should be ok -- however it seems that 
you are not running the version of pywcs you think you are.  Perhaps you 
need to blitz the installation directory (in your case, 
/Users/erwin/lib/python/pywcs) and reinstall.

Mike

On 08/18/2010 02:40 PM, Peter Erwin wrote:
> Hi,
>
> I decided to check out pywcs (in part because using Pyraf to get pixel values from
> RA,Dec pairs seemed to be overkill, and wcwcstran was failing to work for SDSS
> images with declinations close to zero).
>
> The installation ("python setup.py install") seemd to go fine, but I ran into the following when I tried
> running the example from http://stsdas.stsci.edu/astrolib/pywcs/examples.html
>
> <<begin quote>>
> In [164]: hdulist = pyfits.open("pgc1905g_94-220.fits")   # this is an SDSS g-band image
> In [165]: wcs = pywcs.WCS(hdulist[0].header)
> ---------------------------------------------------------------------------
> AttributeError                            Traceback (most recent call last)
>
> /Users/erwin/Documents/Working/ESO_observing/WFI/targets/pgc1905_808/<ipython console>  in<module>()
>
> /Users/erwin/lib/python/pywcs/pywcs.py in __init__(self, header, fobj, key, minerr, relax, naxis)
>      176             self.naxis = wcsprm.naxis
>      177
> -->  178             det2im = self._read_det2im_kw(header, fobj)
>      179             cpdis = self._read_distortion_kw(
>      180                 header, fobj, key=key,dist='CPDIS', err=minerr)
>
> /Users/erwin/lib/python/pywcs/pywcs.py in _read_det2im_kw(self, header, fobj)
>      278         cdelt = [1.,1.]
>      279
> -->  280         if not isinstance(fobj, pyfits.NP_pyfits.HDUList):
>      281             return (None, None)
>      282
>
> AttributeError: 'module' object has no attribute 'NP_pyfits'
> <<end quote>>
>
> My system is: MacBook Pro (2009) running Mac OS 10.6.4, Python 2.6.5 (standard framework install
> from python.org) via ipython 0.10
> numpy 1.4.1
> pyfits 2.3.1 [same problem occurred for pyfits 2.2.2; I
> pywcs v1.9-4.4.4
>
> (All packages are installed inside the framework directory, *except* for pyfits, which installed in
> ~/lib/python )
>
> Any suggestions?
>
>     -- Peter
>
> =============================================================
> Peter Erwin                   Max-Planck-Insitute for Extraterrestrial
> erwin@mpe.mpg.de              Physics, Giessenbachstrasse
> tel. +49 (0)89 30000 3695     85748 Garching, Germany
> fax  +49 (0)89 30000 3495     http://www.mpe.mpg.de/~erwin
>
>
>
> _______________________________________________
> AstroPy mailing list
> AstroPy@scipy.org
> http://mail.scipy.org/mailman/listinfo/astropy
>    


-- 
Michael Droettboom
Science Software Branch
Space Telescope Science Institute
Baltimore, Maryland, USA



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