def test_sip_irac():
"""Test forward and inverse SIP againts astropy.wcs"""
test_file = get_pkg_data_filename(os.path.join('data', 'irac_sip.hdr'))
hdr = fits.Header.fromtextfile(test_file)
crpix1 = hdr['CRPIX1']
crpix2 = hdr['CRPIX2']
wobj = wcs.WCS(hdr)
a_pars = dict(**hdr['A_*'])
b_pars = dict(**hdr['B_*'])
ap_pars = dict(**hdr['AP_*'])
bp_pars = dict(**hdr['BP_*'])
a_order = a_pars.pop('A_ORDER')
b_order = b_pars.pop('B_ORDER')
ap_order = ap_pars.pop('AP_ORDER')
bp_order = bp_pars.pop('BP_ORDER')
del a_pars['A_DMAX']
del b_pars['B_DMAX']
pix = [200, 200]
rel_pix = [200 - crpix1, 200 - crpix2]
sip = SIP([crpix1, crpix2],
a_order,
b_order,
a_pars,
b_pars,
ap_order=ap_order,
ap_coeff=ap_pars,
bp_order=bp_order,
bp_coeff=bp_pars)
foc = wobj.sip_pix2foc([pix], 1)
newpix = wobj.sip_foc2pix(foc, 1)[0]
assert_allclose(sip(*pix), foc[0] - rel_pix)
assert_allclose(sip.inverse(*foc[0]) + foc[0] - rel_pix, newpix - pix)
def test_sip_irac():
"""Test forward and inverse SIP against astropy.wcs"""
test_file = get_pkg_data_filename(os.path.join('data', 'irac_sip.hdr'))
hdr = fits.Header.fromtextfile(test_file)
crpix1 = hdr['CRPIX1']
crpix2 = hdr['CRPIX2']
wobj = wcs.WCS(hdr)
a_pars = dict(**hdr['A_*'])
b_pars = dict(**hdr['B_*'])
ap_pars = dict(**hdr['AP_*'])
bp_pars = dict(**hdr['BP_*'])
a_order = a_pars.pop('A_ORDER')
b_order = b_pars.pop('B_ORDER')
ap_order = ap_pars.pop('AP_ORDER')
bp_order = bp_pars.pop('BP_ORDER')
del a_pars['A_DMAX']
del b_pars['B_DMAX']
pix = [200, 200]
rel_pix = [200 - crpix1, 200 - crpix2]
sip = SIP([crpix1, crpix2], a_order, b_order, a_pars, b_pars,
ap_order=ap_order, ap_coeff=ap_pars, bp_order=bp_order,
bp_coeff=bp_pars)
foc = wobj.sip_pix2foc([pix], 1)
newpix = wobj.sip_foc2pix(foc, 1)[0]
assert_allclose(sip(*pix), foc[0] - rel_pix)
assert_allclose(sip.inverse(*foc[0]) +
foc[0] - rel_pix, newpix - pix)
# Test inverse representations
assert repr(sip.inverse) ==\
"<InverseSIP([<Polynomial2D(2, c0_0=0., c1_0=0.0000114, c2_0=0.00002353, " +\
"c0_1=-0.00000546, c0_2=-0.00000667, c1_1=-0.00001801)>, " +\
"<Polynomial2D(2, c0_0=0., c1_0=-0.00001495, c2_0=0.00000122, c0_1=0.00001975, " +\
"c0_2=-0.00002601, c1_1=0.00002944)>])>"
assert str(sip.inverse) ==\
"Model: InverseSIP\n" +\
" Model: Polynomial2D\n" +\
" Inputs: ('x', 'y')\n" +\
" Outputs: ('z',)\n" +\
" Model set size: 1\n" +\
" Degree: 2\n" +\
" Parameters:\n" +\
" c0_0 c1_0 c2_0 c0_1 c0_2 c1_1 \n" +\
" ---- -------- --------- ---------- ---------- ----------\n" +\
" 0.0 1.14e-05 2.353e-05 -5.463e-06 -6.666e-06 -1.801e-05\n" +\
"\n" +\
" Model: Polynomial2D\n" +\
" Inputs: ('x', 'y')\n" +\
" Outputs: ('z',)\n" +\
" Model set size: 1\n" +\
" Degree: 2\n" +\
" Parameters:\n" +\
" c0_0 c1_0 c2_0 c0_1 c0_2 c1_1 \n" +\
" ---- ---------- --------- --------- ---------- ---------\n" +\
" 0.0 -1.495e-05 1.225e-06 1.975e-05 -2.601e-05 2.944e-05\n"