[AstroPy] pyfits: reading fits data problem

Guillaume Blanc blanc@apc.univ-paris7...
Tue May 26 08:26:39 CDT 2009


Thanks a lot for your quick replies...
Actually my fits file was effectively not "standard". If I set the  
DATE keyword in the standard form (using the sethead script from  
wcstools), it works, even if the fits verifier says: "*** Error:    
File has extra byte(s) after last HDU at byte 63360." ??

But perhaps the pyfits library is too tightly linked to the  
standard... And the error sent was quite enigmatic.

Cheers,
Guillaume

Le 26 mai 09 à 14:57, Malte Tewes a écrit :

> Hi Guillaume,
>
> I can reproduce the error on my side. I would say that the problem is
> your FITS file -- indeed it does not validate on this webpage :
> http://fits.gsfc.nasa.gov/fits_verify.html
>
>
> Cheers,
> Malte
>
>
> On 26 May 2009, at 11:47, Guillaume Blanc wrote:
>
>> Hi,
>>
>> I'm new to python and I'm trying to use pyfits, to read some table
>> data, but if it's work fine on test files, it doesn't work on my  
>> file,
>> and I don't understand why, since I can read it using fv. Pyfits  
>> gives
>> me an error (see below).
>> Any help would be appreciated. Many thanks in advance.
>>
>> Guillaume
>>
>>
>> Here is the python file:
>> -----------------
>> import pyfits
>> import numpy
>> hdulist = pyfits.open('spec10.fits')
>> print hdulist.info()
>> print "HEADER = ", hdulist[0].header
>> scidata = hdulist[0].data
>> print "DATA = " , scidata
>> ---------------
>>
>> Below is the output; file spec10.fits can be downloaded from: http://snovae.free.fr/ftp/spec10.fits
>> Note that I don't understand the first warning, since file size is
>> 123840 bytes. I don't understand either the error on hdulist.data...
>>
>> ---------------
>> % python plotspec.py
>> Warning: File may have been truncated: actual file length (123840) is
>> smaller than the expected size (184320)
>> Filename: spec10.fits
>> No.    Name         Type      Cards   Dimensions   Format
>> 0    PRIMARY     PrimaryHDU      15  (4975, 3)     int32
>> None
>> HEADER =  SIMPLE  =                    T /
>>
>> BITPIX  =                   32 /
>>
>> NAXIS   =                    2 /
>>
>> NAXIS1  =                 4975 /
>>
>> NAXIS2  =                    3 /
>>
>> BSCALE  =   6.240186520248E-07 /
>>
>> BZERO   =       79.45127590903 /
>>
>> DATE    = '18/05/09 10:45:08 ' /
>>
>> CRVAL1  =       3.544000040919 /
>>
>> CD1_1   =   9.999998959014E-05 /
>>
>> Z       =       2.532511414828 /
>>
>> MAG_G   =       21.39270563646 /
>>
>> DECDEG  =       888.0000000000 /
>>
>> RADEG   =       1878.000000000 /
>>
>> COMMENT  Mock Horizon spectrum
>>
>> 14925 items requested but only 0 read
>> Traceback (most recent call last):
>> File "plotspec.py", line 10, in <module>
>>  scidata = hdulist[0].data
>> File "/Library/Frameworks/Python.framework/Versions/2.5.2001/lib/
>> python2.5/site-packages/pyfits/NP_pyfits.py", line 3189, in
>> __getattr__
>>  raw_data.shape=dims
>> ValueError: total size of new array must be unchanged
>> ---------------------------
>>
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>
>
>
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