def test_wcs_no_approximation():
wcs1 = WCS(naxis=2)
wcs1.wcs.ctype = 'DEC--TAN', 'RA---TAN'
wcs1.wcs.set()
data1 = Data(label='Data 1')
data1.coords = wcs1
data1['x'] = np.ones((2, 3))
wcs2 = WCS(naxis=2)
wcs2.wcs.ctype = 'DEC--TAN', 'RA---TAN'
wcs2.wcs.crval = 30, 50
wcs2.wcs.set()
data2 = Data(label='Data 2')
data2.coords = wcs2
data2['x'] = np.ones((2, 3))
link = WCSLink(data1, data2)
with pytest.raises(NoAffineApproximation):
link.as_affine_link(tolerance=0.1)
def test_wcs_affine_approximation():
wcs1 = WCS(naxis=2)
wcs1.wcs.ctype = 'DEC--TAN', 'RA---TAN'
wcs1.wcs.set()
data1 = Data(label='Data 1')
data1.coords = wcs1
data1['x'] = np.ones((2, 3))
wcs2 = WCS(naxis=2)
wcs2.wcs.ctype = 'DEC--TAN', 'RA---TAN'
wcs2.wcs.crpix = -3, 5
wcs2.wcs.cd = [[2, -1], [1, 2]]
wcs2.wcs.set()
data2 = Data(label='Data 2')
data2.coords = wcs2
data2['x'] = np.ones((2, 3))
link = WCSLink(data1, data2)
affine_link = link.as_affine_link(tolerance=0.1)
assert isinstance(affine_link, AffineLink)
assert_allclose(affine_link.matrix,
[[0.4, 0.2, -3.4], [-0.2, 0.4, 4.2], [0, 0, 1]],
atol=1e-5)
x1 = np.array([1.4, 3.2, 2.5])
y1 = np.array([0.2, 4.3, 2.2])
x2, y2 = link.forwards(x1, y1)
x3, y3 = affine_link.forwards(x1, y1)
assert_allclose(x2, x3, atol=1e-5)
assert_allclose(y2, y3, atol=1e-5)
x4, y4 = link.backwards(x1, y1)
x5, y5 = affine_link.backwards(x1, y1)
assert_allclose(x4, x5, atol=1e-5)
assert_allclose(y4, y4, atol=1e-5)
def test_wcs_offset_approximation():
wcs1 = WCS(naxis=2)
wcs1.wcs.ctype = 'DEC--TAN', 'RA---TAN'
wcs1.wcs.set()
data1 = Data(label='Data 1')
data1.coords = wcs1
data1['x'] = np.ones((2, 3))
wcs2 = WCS(naxis=2)
wcs2.wcs.ctype = 'DEC--TAN', 'RA---TAN'
wcs2.wcs.crpix = -3, 5
wcs2.wcs.set()
data2 = Data(label='Data 2')
data2.coords = wcs2
data2['x'] = np.ones((2, 3))
link = WCSLink(data1, data2)
offset_link = link.as_affine_link(tolerance=0.1)
assert isinstance(offset_link, OffsetLink)
assert_allclose(offset_link.offsets, [3, -5])
x1 = np.array([1.4, 3.2, 2.5])
y1 = np.array([0.2, 4.3, 2.2])
x2, y2 = link.forwards(x1, y1)
x3, y3 = offset_link.forwards(x1, y1)
assert_allclose(x2, x3, atol=1e-5)
assert_allclose(y2, y3, atol=1e-5)
x4, y4 = link.backwards(x1, y1)
x5, y5 = offset_link.backwards(x1, y1)
assert_allclose(x4, x5, atol=1e-5)
assert_allclose(y4, y4, atol=1e-5)
def link_data(self,
link_type='pixels',
wcs_fallback_scheme='pixels',
wcs_use_affine=True,
error_on_fail=False):
"""(Re)link loaded data with the desired link type.
All existing links will be replaced.
.. warning::
Any markers added would be removed. You can add back the markers
manually using :meth:`add_markers`. During the markers removal,
pan/zoom will also reset.
Parameters
----------
link_type : {'pixels', 'wcs'}
Choose to link by pixels or WCS.
wcs_fallback_scheme : {None, 'pixels'}
If WCS linking failed, choose to fall back to linking by pixels or not at all.
This is only used when ``link_type='wcs'``.
Choosing `None` may result in some Imviz functionality not working properly.
wcs_use_affine : bool
Use an affine transform to represent the offset between images if possible
(requires that the approximation is accurate to within 1 pixel with the
full WCS transformations). If approximation fails, it will automatically
fall back to full WCS transformation. This is only used when ``link_type='wcs'``.
Affine approximation is much more performant at the cost of accuracy.
error_on_fail : bool
If `True`, any failure in linking will raise an exception.
If `False`, warnings will be emitted as snackbar messages.
When only warnings are emitted and no links are assigned,
some Imviz functionality may not work properly.
Raises
------
ValueError
Invalid inputs or reference data.
"""
if len(self.app.data_collection) <= 1: # No need to link, we are done.
return
if link_type not in ('pixels', 'wcs'):
raise ValueError(
f"link_type must be 'pixels' or 'wcs', got {link_type}")
if link_type == 'wcs' and wcs_fallback_scheme not in (None, 'pixels'):
raise ValueError("wcs_fallback_scheme must be None or 'pixels', "
f"got {wcs_fallback_scheme}")
# Clear any existing markers. Otherwise, re-linking will crash.
self.reset_markers()
refdata, iref = get_reference_image_data(self.app)
links_list = []
ids0 = refdata.pixel_component_ids
ndim_range = range(refdata.ndim)
for i, data in enumerate(self.app.data_collection):
# Do not link with self
if i == iref:
continue
# We are not touching any existing Subsets. They keep their own links.
if not layer_is_image_data(data):
continue
ids1 = data.pixel_component_ids
try:
if link_type == 'pixels':
new_links = [
LinkSame(ids0[i], ids1[i]) for i in ndim_range
]
else: # 'wcs'
wcslink = WCSLink(data1=refdata,
data2=data,
cids1=ids0,
cids2=ids1)
if wcs_use_affine:
try:
new_links = [wcslink.as_affine_link()]
except NoAffineApproximation: # pragma: no cover
new_links = [wcslink]
else:
new_links = [wcslink]
except Exception as e:
if link_type == 'wcs' and wcs_fallback_scheme == 'pixels':
try:
new_links = [
LinkSame(ids0[i], ids1[i]) for i in ndim_range
]
except Exception as e: # pragma: no cover
if error_on_fail:
raise
else:
self.app.hub.broadcast(
SnackbarMessage(
f"Error linking '{data.label}' to '{refdata.label}': "
f"{repr(e)}",
color="warning",
timeout=8000,
sender=self.app))
continue
else:
if error_on_fail:
raise
else:
self.app.hub.broadcast(
SnackbarMessage(
f"Error linking '{data.label}' to '{refdata.label}': "
f"{repr(e)}",
color="warning",
timeout=8000,
sender=self.app))
continue
links_list += new_links
if len(links_list) > 0:
with self.app.data_collection.delay_link_manager_update():
self.app.data_collection.set_links(links_list)
self.app.hub.broadcast(
SnackbarMessage('Images successfully relinked',
color='success',
timeout=8000,
sender=self.app))