def test_wcs_returns_correct_pixel_values_for_random_coords(self, ii):
x = np.random.random(11) * u.arcsec
y = np.random.random(11) * u.arcsec
flux = np.ones(len(x))
hdu = source_utils.make_imagehdu_from_table(x=x,
y=y,
flux=flux,
pix_scale=0.1 * u.arcsec)
the_wcs = wcs.WCS(hdu)
yy, xx = the_wcs.wcs_world2pix(y.to(u.deg), x.to(u.deg), 1)
xx = xx.astype(int)
yy = yy.astype(int)
assert np.all(hdu.data[xx, yy])
def test_stars_are_at_correct_position_for_no_subpixel_accuracy(self):
# weird behaviour for exactly integer coords e.g. (0, 0)
x = np.linspace(-1.0001, 1.0001, 9) * u.arcsec
y = np.linspace(-1.0001, 1.0001, 9) * u.arcsec
flux = np.ones(len(x))
hdu = source_utils.make_imagehdu_from_table(x=x,
y=y,
flux=flux,
pix_scale=0.25 * u.arcsec)
the_wcs = wcs.WCS(hdu)
yy, xx = the_wcs.wcs_world2pix(y.to(u.deg), x.to(u.deg), 1)
xx = np.floor(xx).astype(int)
yy = np.floor(yy).astype(int)
assert np.all(hdu.data[xx, yy])
def test_imagehdu_has_wcs(self):
hdu = source_utils.make_imagehdu_from_table(x=[0], y=[0], flux=[1])
wcs_keys = ["CRPIX1", "CRVAL1", "CDELT1", "CUNIT1"]
assert np.all([key in hdu.header.keys() for key in wcs_keys])
def test_returned_object_is_image_hdu(self):
hdu = source_utils.make_imagehdu_from_table(x=[0], y=[0], flux=[1])
assert isinstance(hdu, fits.ImageHDU)