def test_read_old_style_multiextensionfits(tmpdir):
# Regression test for https://github.com/astropy/ccdproc/issues/664
#
# Prior to astropy 3.1 there was no uncertainty type saved
# in the multiextension fits files generated by CCDData
# because the uncertainty had to be StandardDevUncertainty.
#
# Current version should be able to read those in.
#
size = 4
# Value of the variables below are not important to the test.
data = np.zeros([size, size])
mask = data > 0.9
uncert = np.sqrt(data)
ccd = CCDData(data=data, mask=mask, uncertainty=uncert, unit='adu')
# We'll create the file manually to ensure we have the
# right extension names and no uncertainty type.
hdulist = ccd.to_hdu()
del hdulist[2].header['UTYPE']
file_name = tmpdir.join('old_ccddata_mef.fits').strpath
hdulist.writeto(file_name)
ccd = CCDData.read(file_name)
assert isinstance(ccd.uncertainty, StdDevUncertainty)
def test_read_old_style_multiextensionfits(tmpdir):
# Regression test for https://github.com/astropy/ccdproc/issues/664
#
# Prior to astropy 3.1 there was no uncertainty type saved
# in the multiextension fits files generated by CCDData
# because the uncertainty had to be StandardDevUncertainty.
#
# Current version should be able to read those in.
#
size = 4
# Value of the variables below are not important to the test.
data = np.zeros([size, size])
mask = data > 0.9
uncert = np.sqrt(data)
ccd = CCDData(data=data, mask=mask, uncertainty=uncert, unit='adu')
# We'll create the file manually to ensure we have the
# right extension names and no uncertainty type.
hdulist = ccd.to_hdu()
del hdulist[2].header['UTYPE']
file_name = tmpdir.join('old_ccddata_mef.fits').strpath
hdulist.writeto(file_name)
ccd = CCDData.read(file_name)
assert isinstance(ccd.uncertainty, StdDevUncertainty)
def test_wcs_attribute(tmpdir):
"""
Check that WCS attribute gets added to header, and that if a CCDData
object is created from a FITS file with a header, and the WCS attribute
is modified, then the CCDData object is turned back into an hdu, the
WCS object overwrites the old WCS information in the header.
"""
ccd_data = create_ccd_data()
tmpfile = tmpdir.join('temp.fits')
# This wcs example is taken from the astropy.wcs docs.
wcs = WCS(naxis=2)
wcs.wcs.crpix = np.array(ccd_data.shape) / 2
wcs.wcs.cdelt = np.array([-0.066667, 0.066667])
wcs.wcs.crval = [0, -90]
wcs.wcs.ctype = ["RA---AIR", "DEC--AIR"]
wcs.wcs.set_pv([(2, 1, 45.0)])
ccd_data.header = ccd_data.to_hdu()[0].header
ccd_data.header.extend(wcs.to_header(), useblanks=False)
ccd_data.write(tmpfile.strpath)
# Get the header length after it has been extended by the WCS keywords
original_header_length = len(ccd_data.header)
ccd_new = CCDData.read(tmpfile.strpath)
# WCS attribute should be set for ccd_new
assert ccd_new.wcs is not None
# WCS attribute should be equal to wcs above.
assert ccd_new.wcs.wcs == wcs.wcs
# Converting CCDData object with wcs to an hdu shouldn't
# create duplicate wcs-related entries in the header.
ccd_new_hdu = ccd_new.to_hdu()[0]
assert len(ccd_new_hdu.header) == original_header_length
# Making a CCDData with WCS (but not WCS in the header) should lead to
# WCS information in the header when it is converted to an HDU.
ccd_wcs_not_in_header = CCDData(ccd_data.data, wcs=wcs, unit="adu")
hdu = ccd_wcs_not_in_header.to_hdu()[0]
wcs_header = wcs.to_header()
for k in wcs_header.keys():
# Skip these keywords if they are in the WCS header because they are
# not WCS-specific.
if k in ['', 'COMMENT', 'HISTORY']:
continue
# No keyword from the WCS should be in the header.
assert k not in ccd_wcs_not_in_header.header
# Every keyword in the WCS should be in the header of the HDU
assert hdu.header[k] == wcs_header[k]
# Now check that if WCS of a CCDData is modified, then the CCDData is
# converted to an HDU, the WCS keywords in the header are overwritten
# with the appropriate keywords from the header.
#
# ccd_new has a WCS and WCS keywords in the header, so try modifying
# the WCS.
ccd_new.wcs.wcs.cdelt *= 2
ccd_new_hdu_mod_wcs = ccd_new.to_hdu()[0]
assert ccd_new_hdu_mod_wcs.header['CDELT1'] == ccd_new.wcs.wcs.cdelt[0]
assert ccd_new_hdu_mod_wcs.header['CDELT2'] == ccd_new.wcs.wcs.cdelt[1]
def test_wcs_attribute(ccd_data, tmpdir):
"""
Check that WCS attribute gets added to header, and that if a CCDData
object is created from a FITS file with a header, and the WCS attribute
is modified, then the CCDData object is turned back into an hdu, the
WCS object overwrites the old WCS information in the header.
"""
tmpfile = tmpdir.join('temp.fits')
# This wcs example is taken from the astropy.wcs docs.
wcs = WCS(naxis=2)
wcs.wcs.crpix = np.array(ccd_data.shape) / 2
wcs.wcs.cdelt = np.array([-0.066667, 0.066667])
wcs.wcs.crval = [0, -90]
wcs.wcs.ctype = ["RA---AIR", "DEC--AIR"]
wcs.wcs.set_pv([(2, 1, 45.0)])
ccd_data.header = ccd_data.to_hdu()[0].header
ccd_data.header.extend(wcs.to_header(), useblanks=False)
ccd_data.write(tmpfile.strpath)
# Get the header length after it has been extended by the WCS keywords
original_header_length = len(ccd_data.header)
ccd_new = CCDData.read(tmpfile.strpath)
# WCS attribute should be set for ccd_new
assert ccd_new.wcs is not None
# WCS attribute should be equal to wcs above.
assert ccd_new.wcs.wcs == wcs.wcs
# Converting CCDData object with wcs to an hdu shouldn't
# create duplicate wcs-related entries in the header.
ccd_new_hdu = ccd_new.to_hdu()[0]
assert len(ccd_new_hdu.header) == original_header_length
# Making a CCDData with WCS (but not WCS in the header) should lead to
# WCS information in the header when it is converted to an HDU.
ccd_wcs_not_in_header = CCDData(ccd_data.data, wcs=wcs, unit="adu")
hdu = ccd_wcs_not_in_header.to_hdu()[0]
wcs_header = wcs.to_header()
for k in wcs_header.keys():
# Skip these keywords if they are in the WCS header because they are
# not WCS-specific.
if k in ['', 'COMMENT', 'HISTORY']:
continue
# No keyword from the WCS should be in the header.
assert k not in ccd_wcs_not_in_header.header
# Every keyword in the WCS should be in the header of the HDU
assert hdu.header[k] == wcs_header[k]
# Now check that if WCS of a CCDData is modified, then the CCDData is
# converted to an HDU, the WCS keywords in the header are overwritten
# with the appropriate keywords from the header.
#
# ccd_new has a WCS and WCS keywords in the header, so try modifying
# the WCS.
ccd_new.wcs.wcs.cdelt *= 2
ccd_new_hdu_mod_wcs = ccd_new.to_hdu()[0]
assert ccd_new_hdu_mod_wcs.header['CDELT1'] == ccd_new.wcs.wcs.cdelt[0]
assert ccd_new_hdu_mod_wcs.header['CDELT2'] == ccd_new.wcs.wcs.cdelt[1]
