[AstroPy] {SunPy} Re: Unable to Save Compressed HDU

[Harsh Mathur]

Also Here are the versions

astropy          3.1.1

sunpy            0.9.6

numpy            1.16.0

Regards
Harsh Mathur
harshmathur.1990 at gmail.com

*“Perseverance is the hard work you do after you get tired of doing the
hard work you already did."*


On Wed, Jan 30, 2019 at 10:34 PM Harsh Mathur <harshmathur.1990 at gmail.com>
wrote:

> Hi,
>
> Please find the steps to reproduce:
>
> 1. Download the data and header pickled from here (
> https://drive.google.com/drive/folders/10V7ruXr3As9dD5o416VLTh_ZIMAH3POw?usp=sharing
> )
>
> 2. Python code:
>
> *import* *pickle*
>
> *import* *sunpy.io.fits*
>
> *from* *astropy.io <http://astropy.io>* *import* fits
>
> data = pickle.loads(open('fits_data.data', 'rb').read())
>
> header = pickle.loads(open('header.data', 'rb').read())
>
> sunpy.io.fits.write('sample.fits', data, header,
> hdu_type=fits.CompImageHDU)
>
> 3. Before saving we can also confirm the data is correct by
>
> *import* *matplotlib.pyplot* *as* *plt*
>
> plt.imshow(data, cmap='gray')
>
> plt.show()
>
> Attached is the plt.show() output.
>
> Thanks for looking into this.
>
> Regards
> Harsh Mathur
> harshmathur.1990 at gmail.com
>
> *“Perseverance is the hard work you do after you get tired of doing the
> hard work you already did."*
>
>
> On Wed, Jan 30, 2019 at 2:29 PM Christoph Deil <
> deil.christoph at googlemail.com> wrote:
>
>>
>>
>> On 30. Jan 2019, at 09:41, Harsh Mathur <harshmathur.1990 at gmail.com>
>> wrote:
>>
>> Hi,
>> I have a fits file which normally takes around 132 MB. I want to save it
>> with compressed HDU.
>>
>> I tried both with astropy and sunpy, but for some reason it is
>> not working. To be specific, it is saving empty HDU (i.e. the grid is only
>> filled with nans).
>>
>> Here's what I did with astropy:
>>
>> from astropy.io import fits
>> header_object = self._get_header_object(header)
>> comp_hdu = fits.CompImageHDU(data=data, header=header_object)
>> comp_hdu.writeto(filename, output_verify='fix')
>>
>> Here's what I did with sunpy:
>> import sunpy.io.fits
>> sunpy.io.fits.write(
>>             filename,
>>             data,
>>             header,
>>             hdu_type=fits.CompImageHDU
>>         )
>>
>> I tried to debug using ipdb and checked just before the save instruction,
>> the data and header are present and not empty, just that its not saving.
>>
>> The worst thing is, there is no error for me debug. Any help is
>> appreciated.
>>
>> Thank you in advance.
>>
>> Regards
>> Harsh Mathur
>> harshmathur.1990 at gmail.com
>>
>> *“Perseverance is the hard work you do after you get tired of doing the
>> hard work you already did."*
>> _______________________________________________
>> AstroPy mailing list
>> AstroPy at python.org
>> https://mail.python.org/mailman/listinfo/astropy
>>
>>
>>
>> Hi Harsh,
>>
>> Can you try to create a standalone test case that we can run to try and
>> reproduce / debug the issue?
>> E.g. make up some data using numpy.ones or numpy.random, provide a code
>> snippet we can just copy & paste & run.
>>
>> Also please mention your Numpy and Astropy version number.
>>
>> It’s probably not your exact issue, but there is this issue
>> https://github.com/astropy/astropy/issues/2150
>> which causes issues sometimes, but only when writing certain Numpy arrays
>> and when using compression.
>>
>> Without an example to reproduce, it’s likely hard to help figure out
>> exactly what goes wrong in your case.
>>
>> Christoph
>> _______________________________________________
>> AstroPy mailing list
>> AstroPy at python.org
>> https://mail.python.org/mailman/listinfo/astropy
>>
> --
> You received this message because you are subscribed to the Google Groups
> "SunPy" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to sunpy+unsubscribe at googlegroups.com.
> To post to this group, send email to sunpy at googlegroups.com.
> Visit this group at https://groups.google.com/group/sunpy.
> For more options, visit https://groups.google.com/d/optout.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/astropy/attachments/20190130/b8f94b83/attachment.html>