Hi,
BITPIX = -32 is a valid value and just means that the array is
represented as IEEE 32-bit floating point values, so that shouldn't
be a problem.
Cheers,
Seb
On 31 Jan 2008, at 14:59, Xavier Calbet wrote:
> One more thing, you might want to have a look at your fits header
> before
> you write your FITS file (print $hdr->{BITPIX} maybe) just to
> check and
> see whether you have garbage in there or not. In any case you can also
> do
>
> $hdr->{BITPIX}=32
>
> before you write the file.
>
> Xavier Calbet
>
>
> On Jan 31, 2008 3:55 PM, Xavier Calbet <[EMAIL PROTECTED]> wrote:
>> When I read your original file I get (as you do) different results
>> with the plotting
>> and printing. If I modify BITPIX=-32 to BITPIX=32 I get consistent
>> results.
>>
>> Cheers,
>>
>> Xavier Calbet
>>
>>
>> On Jan 31, 2008 3:41 PM, PAUL <[EMAIL PROTECTED]> wrote:
>>> Hmmm... that does seem strange, but then looking at all the headers
>>> of the FITS files I have, they all have BITPIX=-32. (Even FITS which
>>> have not been hacked using PDL). Is BITPIX actually still used?
>>>
>>> The sub which I used to write many FITS is here:
>>>
>>>
>>> ##################################################
>>> sub WriteFits { ##################################
>>> for($i=0;$i<$N_data;++$i) {
>>> ($suffix) = @_;
>>> $fitsname = $allnames[$i].$suffix.".fits";
>>> $newpid = $new_master_data(:,:,$i);
>>> $newpid = $newpid->float;
>>> $minpid = min($newpid);
>>> $maxpid = max($newpid);
>>> $hdr->{MINVAL} = $minpid;
>>> $hdr->{MAXVAL} = $maxpid;
>>> $newpid -> sethdr($hdr);
>>> wfits $newpid, $fitsname;
>>> print "FITS file FITS/$fitsname created!\n";
>>> system 'mv',$fitsname,$fitsdirectory;
>>> }
>>> system 'mv',$filename,$donedirectory;
>>> } # Ends the WriteFits sub. ######################
>>> ##################################################
>>>
>>> However, I've used this same routine to make hundreds of other FITS
>>> in this way, and I've never seen this weird problem before!
>>>
>>> cheers,
>>>
>>> Paul
>>>
>>>
>>>
>>>
>>> On 31 Jan 2008, at 14:17, Xavier Calbet wrote:
>>>
>>>> Don't know if it has anything to do with it, but your fits
>>>> header has a value of BITPIX=-32 (negative!!!)
>>>> This value is the number of bits per pixel in the image
>>>> and should always be positive.
>>>> If foo.fits has been written by PDL then it is strange.
>>>> Can you extract the PDL code where you write this file?
>>>>
>>>> Xavier Calbet
>>>>
>>>>
>>>> On Jan 31, 2008 2:58 PM, PAUL <[EMAIL PROTECTED]> wrote:
>>>>> Hi,
>>>>>
>>>>> I've encountered a strange effect when reading a fits file in the
>>>>> usual way (written with wfits, read with rfits as I usually do).
>>>>>
>>>>> The problem is, when I try and plot the piddle as a scatter plot
>>>>> ($win->points($x,$y)) it plots completely different values than
>>>>> when
>>>>> you simply print the piddle to the screen.
>>>>> I've tried writing the data to an ASCII file using "wcols" and
>>>>> then
>>>>> re-reading it, but this strange problem remains.
>>>>>
>>>>> What's going wrong? I've attached the fits file to the email.
>>>>>
>>>>> thanks,
>>>>>
>>>>> Paul
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Perldl mailing list
>>>>> [email protected]
>>>>> http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
>>>>>
>>>>>
>>>
>>>
>>
>
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