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import pytest
import warnings
import os
import tempfile
from astropy.io import fits
import numpy as np
from ..wcs_utils import (WCS, drop_axis, wcs_swapaxes, add_stokes_axis_to_wcs,
axis_names, slice_wcs, check_equality, strip_wcs_from_header)
from . import path
def test_wcs_dropping():
wcs = WCS(naxis=4)
wcs.wcs.pc = np.zeros([4, 4])
np.fill_diagonal(wcs.wcs.pc, np.arange(1, 5))
pc = wcs.wcs.pc # for later use below
dropped = drop_axis(wcs, 0)
assert np.all(dropped.wcs.get_pc().diagonal() == np.array([2, 3, 4]))
dropped = drop_axis(wcs, 1)
assert np.all(dropped.wcs.get_pc().diagonal() == np.array([1, 3, 4]))
dropped = drop_axis(wcs, 2)
assert np.all(dropped.wcs.get_pc().diagonal() == np.array([1, 2, 4]))
dropped = drop_axis(wcs, 3)
assert np.all(dropped.wcs.get_pc().diagonal() == np.array([1, 2, 3]))
wcs = WCS(naxis=4)
wcs.wcs.cd = pc
dropped = drop_axis(wcs, 0)
assert np.all(dropped.wcs.get_pc().diagonal() == np.array([2, 3, 4]))
dropped = drop_axis(wcs, 1)
assert np.all(dropped.wcs.get_pc().diagonal() == np.array([1, 3, 4]))
dropped = drop_axis(wcs, 2)
assert np.all(dropped.wcs.get_pc().diagonal() == np.array([1, 2, 4]))
dropped = drop_axis(wcs, 3)
assert np.all(dropped.wcs.get_pc().diagonal() == np.array([1, 2, 3]))
def test_wcs_swapping():
wcs = WCS(naxis=4)
wcs.wcs.pc = np.zeros([4, 4])
np.fill_diagonal(wcs.wcs.pc, np.arange(1, 5))
pc = wcs.wcs.pc # for later use below
swapped = wcs_swapaxes(wcs, 0, 1)
assert np.all(swapped.wcs.get_pc().diagonal() == np.array([2, 1, 3, 4]))
swapped = wcs_swapaxes(wcs, 0, 3)
assert np.all(swapped.wcs.get_pc().diagonal() == np.array([4, 2, 3, 1]))
swapped = wcs_swapaxes(wcs, 2, 3)
assert np.all(swapped.wcs.get_pc().diagonal() == np.array([1, 2, 4, 3]))
wcs = WCS(naxis=4)
wcs.wcs.cd = pc
swapped = wcs_swapaxes(wcs, 0, 1)
assert np.all(swapped.wcs.get_pc().diagonal() == np.array([2, 1, 3, 4]))
swapped = wcs_swapaxes(wcs, 0, 3)
assert np.all(swapped.wcs.get_pc().diagonal() == np.array([4, 2, 3, 1]))
swapped = wcs_swapaxes(wcs, 2, 3)
assert np.all(swapped.wcs.get_pc().diagonal() == np.array([1, 2, 4, 3]))
def test_add_stokes():
wcs = WCS(naxis=3)
for ii in range(4):
outwcs = add_stokes_axis_to_wcs(wcs, ii)
assert outwcs.wcs.naxis == 4
def test_axis_names(data_adv, data_vad):
wcs = WCS(str(data_adv))
assert axis_names(wcs) == ['RA', 'DEC', 'VOPT']
wcs = WCS(str(data_vad))
assert axis_names(wcs) == ['VOPT', 'RA', 'DEC']
def test_wcs_slice():
wcs = WCS(naxis=3)
wcs.wcs.crpix = [50., 45., 30.]
wcs_new = slice_wcs(wcs, (slice(10,20), slice(None), slice(20,30)))
np.testing.assert_allclose(wcs_new.wcs.crpix, [30., 45., 20.])
def test_wcs_slice_reversal():
wcs = WCS(naxis=3)
wcs.wcs.crpix = [50., 45., 30.]
wcs.wcs.crval = [0., 0., 0.]
wcs.wcs.cdelt = [1., 1., 1.]
wcs_new = slice_wcs(wcs, (slice(None, None, -1), slice(None), slice(None)),
shape=[100., 150., 200.])
spaxis = wcs.sub([0]).wcs_pix2world(np.arange(100), 0)
new_spaxis = wcs_new.sub([0]).wcs_pix2world(np.arange(100), 0)
np.testing.assert_allclose(spaxis, new_spaxis[::-1])
def test_reversal_roundtrip():
wcs = WCS(naxis=3)
wcs.wcs.crpix = [50., 45., 30.]
wcs.wcs.crval = [0., 0., 0.]
wcs.wcs.cdelt = [1., 1., 1.]
wcs_new = slice_wcs(wcs, (slice(None, None, -1), slice(None), slice(None)),
shape=[100., 150., 200.])
spaxis = wcs.sub([0]).wcs_pix2world(np.arange(100), 0)
new_spaxis = wcs_new.sub([0]).wcs_pix2world(np.arange(100), 0)
np.testing.assert_allclose(spaxis, new_spaxis[::-1])
re_reverse = slice_wcs(wcs_new, (slice(None, None, -1), slice(None), slice(None)),
shape=[100., 150., 200.])
new_spaxis = re_reverse.sub([0]).wcs_pix2world(np.arange(100), 0)
np.testing.assert_allclose(spaxis, new_spaxis[::-1])
#These are NOT equal, but they are equivalent: CRVAL and CRPIX are shifted
#by an acceptable amount
# assert check_equality(wcs, re_reverse)
re_re_reverse = slice_wcs(re_reverse, (slice(None, None, -1), slice(None),
slice(None)),
shape=[100., 150., 200.])
re_re_re_reverse = slice_wcs(re_re_reverse, (slice(None, None, -1),
slice(None), slice(None)),
shape=[100., 150., 200.])
assert check_equality(re_re_re_reverse, re_reverse)
def test_wcs_comparison():
wcs1 = WCS(naxis=3)
wcs1.wcs.crpix = np.array([50., 45., 30.], dtype='float32')
wcs2 = WCS(naxis=3)
wcs2.wcs.crpix = np.array([50., 45., 30.], dtype='float64')
wcs3 = WCS(naxis=3)
wcs3.wcs.crpix = np.array([50., 45., 31.], dtype='float64')
wcs4 = WCS(naxis=3)
wcs4.wcs.crpix = np.array([50., 45., 30.0001], dtype='float64')
assert check_equality(wcs1,wcs2)
assert not check_equality(wcs1,wcs3)
assert check_equality(wcs1, wcs3, wcs_tolerance=1.0e1)
assert not check_equality(wcs1,wcs4)
assert check_equality(wcs1, wcs4, wcs_tolerance=1e-3)
@pytest.mark.parametrize('fn', ('cubewcs1.hdr', 'cubewcs2.hdr'))
def test_strip_wcs(fn):
header1 = fits.Header.fromtextfile(path(fn))
header1_stripped = strip_wcs_from_header(header1)
with open(path(fn),'r') as fh:
hdrlines = fh.readlines()
fd, newfn = tempfile.mkstemp(suffix='.hdr')
hdrlines.insert(-20,"\n")
hdrlines.insert(-1,"\n")
with os.fdopen(fd,'w') as fh:
fh.writelines(hdrlines)
header2 = fits.Header.fromtextfile(path(newfn))
header2_stripped = strip_wcs_from_header(header2)
os.remove(newfn)
assert header1_stripped == header2_stripped
def test_wcs_slice_unmatched_celestial():
wcs = WCS(naxis=3)
wcs.wcs.ctype = ['RA---TAN', 'DEC--TAN', 'FREQ']
wcs.wcs.crpix = [50., 45., 30.]
# drop RA
with warnings.catch_warnings(record=True) as wrn:
wcs_new = drop_axis(wcs, 0)
assert 'is being removed' in str(wrn[-1].message)
# drop Dec
with warnings.catch_warnings(record=True) as wrn:
wcs_new = drop_axis(wcs, 1)
assert 'is being removed' in str(wrn[-1].message)
with warnings.catch_warnings(record=True) as wrn:
wcs_new = slice_wcs(wcs, (slice(10,20), 0, slice(20,30)),
drop_degenerate=True)
assert 'is being removed' in str(wrn[-1].message)
def test_wcs_downsampling():
"""
Regression tests for #525
These are a series of simple tests I verified with pen and paper, but it's
always worth checking me again.
"""
wcs = WCS(naxis=1)
wcs.wcs.ctype = ['FREQ',]
wcs.wcs.crpix = [1.,]
nwcs = slice_wcs(wcs, slice(0, None, 1))
assert nwcs.wcs.crpix[0] == 1
nwcs = slice_wcs(wcs, slice(0, None, 2))
assert nwcs.wcs.crpix[0] == 0.75
nwcs = slice_wcs(wcs, slice(0, None, 4))
assert nwcs.wcs.crpix[0] == 0.625
nwcs = slice_wcs(wcs, slice(2, None, 1))
assert nwcs.wcs.crpix[0] == -1
nwcs = slice_wcs(wcs, slice(2, None, 2))
assert nwcs.wcs.crpix[0] == -0.25
nwcs = slice_wcs(wcs, slice(2, None, 4))
assert nwcs.wcs.crpix[0] == 0.125
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