def insert_skycomponent(im: Image, sc: Skycomponent, insert_method=''):
""" Insert a Skycomponent into an image
:param params:
:param im:
:param sc: SkyComponent or list of SkyComponents
:returns: image
"""
assert type(im) == Image
nchan, npol, ny, nx = im.data.shape
if not isinstance(sc, collections.Iterable):
sc = [sc]
for comp in sc:
assert comp.shape == 'Point', "Cannot handle shape %s" % comp.shape
assert_same_chan_pol(im, comp)
if insert_method == "Lanczos":
pixloc = skycoord_to_pixel(comp.direction, im.wcs, 0, 'wcs')
_L2D(im.data, pixloc[1], pixloc[0], comp.flux)
else:
pixloc = numpy.round(
skycoord_to_pixel(comp.direction, im.wcs, 1,
'wcs')).astype('int')
x, y = pixloc[0], pixloc[1]
if x >= 0 and x < nx and y >= 0 and y < ny:
im.data[:, :, y, x] += comp.flux
return im
def _pixel_scale_angle_at_skycoord(skycoord, wcs, offset=1.0 * u.arcsec):
"""
Calculate the pixel scale and WCS rotation angle at the position of
a SkyCoord coordinate.
Parameters
----------
skycoord : `~astropy.coordinates.SkyCoord`
The SkyCoord coordinate.
wcs : WCS object
A world coordinate system (WCS) transformation that supports the
`astropy shared interface for WCS
<https://docs.astropy.org/en/stable/wcs/wcsapi.html>`_ (e.g.
`astropy.wcs.WCS`, `gwcs.wcs.WCS`).
offset : `~astropy.units.Quantity`
A small angular offset to use to compute the pixel scale and
position angle.
Returns
-------
scale : `~astropy.units.Quantity`
The pixel scale in arcsec/pixel.
angle : `~astropy.units.Quantity`
The angle (in degrees) measured counterclockwise from the
positive x axis to the "North" axis of the celestial coordinate
system.
Notes
-----
If distortions are present in the image, the x and y pixel scales
likely differ. This function computes a single pixel scale along
the North/South axis.
"""
try:
x, y = wcs.world_to_pixel(skycoord)
# We take a point directly North (i.e. latitude offset) the input
# sky coordinate and convert it to pixel coordinates, then we use the
# pixel deltas between the input and offset sky coordinate to
# calculate the pixel scale and angle.
skycoord_offset = skycoord.directional_offset_by(0.0, offset)
x_offset, y_offset = wcs.world_to_pixel(skycoord_offset)
except AttributeError:
# for Astropy < 3.1 WCS support
x, y = skycoord_to_pixel(skycoord, wcs)
coord = skycoord.represent_as('unitspherical')
coord_new = UnitSphericalRepresentation(coord.lon, coord.lat + offset)
coord_offset = skycoord.realize_frame(coord_new)
x_offset, y_offset = skycoord_to_pixel(coord_offset, wcs)
dx = x_offset - x
dy = y_offset - y
scale = offset.to(u.arcsec) / (np.hypot(dx, dy) * u.pixel)
angle = (np.arctan2(dy, dx) * u.radian).to(u.deg)
return scale, angle
def test_skycoord_to_pixel_swapped():
# Regression test for a bug that caused skycoord_to_pixel and
# pixel_to_skycoord to not work correctly if the axes were swapped in the
# WCS.
# Import astropy.coordinates here to avoid circular imports
from astropy.coordinates import SkyCoord
header = get_pkg_data_contents('maps/1904-66_TAN.hdr', encoding='binary')
wcs = WCS(header)
wcs_swapped = wcs.sub([WCSSUB_LATITUDE, WCSSUB_LONGITUDE])
ref = SkyCoord(0.1 * u.deg, -89. * u.deg, frame='icrs')
xp1, yp1 = skycoord_to_pixel(ref, wcs)
xp2, yp2 = skycoord_to_pixel(ref, wcs_swapped)
assert_allclose(xp1, xp2)
assert_allclose(yp1, yp2)
# WCS is in FK5 so we need to transform back to ICRS
new1 = pixel_to_skycoord(xp1, yp1, wcs).transform_to('icrs')
new2 = pixel_to_skycoord(xp1, yp1, wcs_swapped).transform_to('icrs')
assert_allclose(new1.ra.degree, new2.ra.degree)
assert_allclose(new1.dec.degree, new2.dec.degree)
def show_components(im, comps, npixels=128, fig=None, vmax=None, vmin=None):
""" Show components against an image
:param im:
:param comps:
:param npixels:
:param fig:
:return:
"""
import matplotlib.pyplot as plt
if vmax is None:
vmax = numpy.max(im.data[0, 0, ...])
if vmin is None:
vmin = numpy.min(im.data[0, 0, ...])
if not fig:
fig = plt.figure()
plt.clf()
for isc, sc in enumerate(comps):
newim = copy_image(im)
plt.subplot(111, projection=newim.wcs.sub([1, 2]))
centre = numpy.round(skycoord_to_pixel(sc.direction, newim.wcs, 1, 'wcs')).astype('int')
newim.data = newim.data[:, :,
(centre[1] - npixels // 2):(centre[1] + npixels // 2),
(centre[0] - npixels // 2):(centre[0] + npixels // 2)]
newim.wcs.wcs.crpix[0] -= centre[0] - npixels // 2
newim.wcs.wcs.crpix[1] -= centre[1] - npixels // 2
plt.imshow(newim.data[0, 0, ...], origin='lower', cmap='Greys', vmax=vmax, vmin=vmin)
x, y = skycoord_to_pixel(sc.direction, newim.wcs, 0, 'wcs')
plt.plot(x, y, marker='+', color='red')
plt.title('Name = %s, flux = %s' % (sc.name, sc.flux))
plt.show()
def test_skycoord_to_pixel_swapped():
# Regression test for a bug that caused skycoord_to_pixel and
# pixel_to_skycoord to not work correctly if the axes were swapped in the
# WCS.
# Import astropy.coordinates here to avoid circular imports
from astropy.coordinates import SkyCoord
header = get_pkg_data_contents('data/maps/1904-66_TAN.hdr',
encoding='binary')
wcs = WCS(header)
wcs_swapped = wcs.sub([WCSSUB_LATITUDE, WCSSUB_LONGITUDE])
ref = SkyCoord(0.1 * u.deg, -89. * u.deg, frame='icrs')
xp1, yp1 = skycoord_to_pixel(ref, wcs)
xp2, yp2 = skycoord_to_pixel(ref, wcs_swapped)
assert_allclose(xp1, xp2)
assert_allclose(yp1, yp2)
# WCS is in FK5 so we need to transform back to ICRS
new1 = pixel_to_skycoord(xp1, yp1, wcs).transform_to('icrs')
new2 = pixel_to_skycoord(xp1, yp1, wcs_swapped).transform_to('icrs')
assert_allclose(new1.ra.degree, new2.ra.degree)
assert_allclose(new1.dec.degree, new2.dec.degree)
def crop_to_training_area(image_path, out_path, freq, pad_factor=1.0):
"""
For a given SDC1 image, write a new FITS file containing only the training
area.
Training area defined by RA/Dec, which doesn't map perfectly to pixel values.
Args:
image_path (`str`): Path to input image
out_path (`str`): Path to write sub-image to
freq (`int`): [560, 1400, 9200] SDC1 image frequency (different training areas)
pad_factor (`float`, optional): Area scaling factor to include edges
"""
hdu = fits.open(image_path)[0]
wcs = WCS(hdu.header)
# Lookup training limits for given frequency
ra_max = TRAIN_LIM[freq]["ra_max"]
ra_min = TRAIN_LIM[freq]["ra_min"]
dec_max = TRAIN_LIM[freq]["dec_max"]
dec_min = TRAIN_LIM[freq]["dec_min"]
# Centre of training area pixel coordinate:
train_centre = SkyCoord(
ra=(ra_max + ra_min) / 2,
dec=(dec_max + dec_min) / 2,
frame="fk5",
unit="deg",
)
# Opposing corners of training area:
train_min = SkyCoord(
ra=ra_min,
dec=dec_min,
frame="fk5",
unit="deg",
)
train_max = SkyCoord(
ra=ra_max,
dec=dec_max,
frame="fk5",
unit="deg",
)
# Training area approx width
pixel_width = (abs(
skycoord_to_pixel(train_max, wcs)[0] -
skycoord_to_pixel(train_min, wcs)[0]) * pad_factor)
# Training area approx height
pixel_height = (abs(
skycoord_to_pixel(train_max, wcs)[1] -
skycoord_to_pixel(train_min, wcs)[1]) * pad_factor)
save_subimage(
image_path,
out_path,
skycoord_to_pixel(train_centre, wcs),
(pixel_height, pixel_width),
)
def skycoord_to_pixel_scale_angle(skycoord, wcs, small_offset=1 * u.arcsec):
"""
Convert a set of SkyCoord coordinates into pixel coordinates, pixel
scales, and position angles.
Parameters
----------
skycoord : `~astropy.coordinates.SkyCoord`
Sky coordinates
wcs : `~astropy.wcs.WCS`
The WCS transformation to use
small_offset : `~astropy.units.Quantity`
A small offset to use to compute the angle
Returns
-------
pixcoord : `~regions.PixCoord`
Pixel coordinates
scale : float
The pixel scale at each location, in degrees/pixel
angle : `~astropy.units.Quantity`
The position angle of the celestial coordinate system in pixel space.
"""
# Convert to pixel coordinates
x, y = skycoord_to_pixel(skycoord, wcs, mode=skycoord_to_pixel_mode)
pixcoord = PixCoord(x=x, y=y)
# We take a point directly 'above' (in latitude) the position requested
# and convert it to pixel coordinates, then we use that to figure out the
# scale and position angle of the coordinate system at the location of
# the points.
# Find the coordinates as a representation object
r_old = skycoord.represent_as('unitspherical')
# Add a a small perturbation in the latitude direction (since longitude
# is more difficult because it is not directly an angle).
dlat = small_offset
r_new = UnitSphericalRepresentation(r_old.lon, r_old.lat + dlat)
coords_offset = skycoord.realize_frame(r_new)
# Find pixel coordinates of offset coordinates
x_offset, y_offset = skycoord_to_pixel(coords_offset,
wcs,
mode=skycoord_to_pixel_mode)
# Find vector
dx = x_offset - x
dy = y_offset - y
# Find the length of the vector
scale = np.hypot(dx, dy) / dlat.to('degree').value
# Find the position angle
angle = np.arctan2(dy, dx) * u.radian
return pixcoord, scale, angle
def skycoord_to_pixel_scale_angle(skycoord, wcs, small_offset=1 * u.arcsec):
"""
Convert a set of SkyCoord coordinates into pixel coordinates, pixel
scales, and position angles.
Parameters
----------
skycoord : `~astropy.coordinates.SkyCoord`
Sky coordinates
wcs : `~astropy.wcs.WCS`
The WCS transformation to use
small_offset : `~astropy.units.Quantity`
A small offset to use to compute the angle
Returns
-------
pixcoord : `~regions.PixCoord`
Pixel coordinates
scale : float
The pixel scale at each location, in degrees/pixel
angle : `~astropy.units.Quantity`
The position angle of the celestial coordinate system in pixel space.
"""
# Convert to pixel coordinates
x, y = skycoord_to_pixel(skycoord, wcs, mode=skycoord_to_pixel_mode)
pixcoord = PixCoord(x=x, y=y)
# We take a point directly 'above' (in latitude) the position requested
# and convert it to pixel coordinates, then we use that to figure out the
# scale and position angle of the coordinate system at the location of
# the points.
# Find the coordinates as a representation object
r_old = skycoord.represent_as('unitspherical')
# Add a a small perturbation in the latitude direction (since longitude
# is more difficult because it is not directly an angle).
dlat = small_offset
r_new = UnitSphericalRepresentation(r_old.lon, r_old.lat + dlat)
coords_offset = skycoord.realize_frame(r_new)
# Find pixel coordinates of offset coordinates
x_offset, y_offset = skycoord_to_pixel(coords_offset, wcs,
mode=skycoord_to_pixel_mode)
# Find vector
dx = x_offset - x
dy = y_offset - y
# Find the length of the vector
scale = np.hypot(dx, dy) / dlat.to('degree').value
# Find the position angle
angle = np.arctan2(dy, dx) * u.radian
return pixcoord, scale, angle
def skycoord_to_pixel_scale_angle(coords, wcs):
"""
Convert a set of SkyCoord coordinates into pixel coordinates, pixel
scales, and position angles.
Parameters
----------
coords : `~astropy.coordinates.SkyCoord`
The coordinates to convert
wcs : `~astropy.wcs.WCS`
The WCS transformation to use
Returns
-------
x, y : `~numpy.ndarray`
The x and y pixel coordinates corresponding to the input coordinates
scale : `~astropy.units.Quantity`
The pixel scale at each location, in degrees/pixel
angle : `~astropy.units.Quantity`
The position angle of the celestial coordinate system in pixel space.
"""
# Convert to pixel coordinates
x, y = skycoord_to_pixel(coords, wcs, mode=skycoord_to_pixel_mode)
# We take a point directly 'above' (in latitude) the position requested
# and convert it to pixel coordinates, then we use that to figure out the
# scale and position angle of the coordinate system at the location of
# the points.
# Find the coordinates as a representation object
r_old = coords.represent_as('unitspherical')
# Add a a small perturbation in the latitude direction (since longitude
# is more difficult because it is not directly an angle).
dlat = 1 * u.arcsec
r_new = UnitSphericalRepresentation(r_old.lon, r_old.lat + dlat)
coords_offset = coords.realize_frame(r_new)
# Find pixel coordinates of offset coordinates
x_offset, y_offset = skycoord_to_pixel(coords_offset,
wcs,
mode=skycoord_to_pixel_mode)
# Find vector
dx = x_offset - x
dy = y_offset - y
# Find the length of the vector
scale = np.hypot(dx, dy) * u.pixel / dlat
# Find the position angle
angle = np.arctan2(dy, dx) * u.radian
return x, y, scale, angle
def skycoord_to_pixel_scale_angle(coords, wcs):
"""
Convert a set of SkyCoord coordinates into pixel coordinates, pixel
scales, and position angles.
Parameters
----------
coords : `~astropy.coordinates.SkyCoord`
The coordinates to convert
wcs : `~astropy.wcs.WCS`
The WCS transformation to use
Returns
-------
x, y : `~numpy.ndarray`
The x and y pixel coordinates corresponding to the input coordinates
scale : `~astropy.units.Quantity`
The pixel scale at each location, in degrees/pixel
angle : `~astropy.units.Quantity`
The position angle of the celestial coordinate system in pixel space.
"""
# Convert to pixel coordinates
x, y = skycoord_to_pixel(coords, wcs, mode=skycoord_to_pixel_mode)
# We take a point directly 'above' (in latitude) the position requested
# and convert it to pixel coordinates, then we use that to figure out the
# scale and position angle of the coordinate system at the location of
# the points.
# Find the coordinates as a representation object
r_old = coords.represent_as('unitspherical')
# Add a a small perturbation in the latitude direction (since longitude
# is more difficult because it is not directly an angle).
dlat = 1 * u.arcsec
r_new = UnitSphericalRepresentation(r_old.lon, r_old.lat + dlat)
coords_offset = coords.realize_frame(r_new)
# Find pixel coordinates of offset coordinates
x_offset, y_offset = skycoord_to_pixel(coords_offset, wcs,
mode=skycoord_to_pixel_mode)
# Find vector
dx = x_offset - x
dy = y_offset - y
# Find the length of the vector
scale = np.hypot(dx, dy) * u.pixel / dlat
# Find the position angle
angle = np.arctan2(dy, dx) * u.radian
return x, y, scale, angle
def pixel_scale_angle_at_skycoord(skycoord, wcs, offset=1. * u.arcsec):
"""
Calculate the pixel scale and WCS rotation angle at the position of
a SkyCoord coordinate.
Parameters
----------
skycoord : `~astropy.coordinates.SkyCoord`
The SkyCoord coordinate.
wcs : `~astropy.wcs.WCS`
The world coordinate system (WCS) transformation to use.
offset : `~astropy.units.Quantity`
A small angular offset to use to compute the pixel scale and
position angle.
Returns
-------
scale : `~astropy.units.Quantity`
The pixel scale in arcsec/pixel.
angle : `~astropy.units.Quantity`
The angle (in degrees) measured counterclockwise from the
positive x axis to the "North" axis of the celestial coordinate
system.
Notes
-----
If distortions are present in the image, the x and y pixel scales
likely differ. This function computes a single pixel scale along
the North/South axis.
"""
# We take a point directly "above" (in latitude) the input position
# and convert it to pixel coordinates, then we use the pixel deltas
# between the input and offset point to calculate the pixel scale and
# angle.
# Find the coordinates as a representation object
coord = skycoord.represent_as('unitspherical')
# Add a a small perturbation in the latitude direction (since longitude
# is more difficult because it is not directly an angle)
coord_new = UnitSphericalRepresentation(coord.lon, coord.lat + offset)
coord_offset = skycoord.realize_frame(coord_new)
# Find pixel coordinates of offset coordinates and pixel deltas
x_offset, y_offset = skycoord_to_pixel(coord_offset, wcs, mode='all')
x, y = skycoord_to_pixel(skycoord, wcs, mode='all')
dx = x_offset - x
dy = y_offset - y
scale = offset.to(u.arcsec) / (np.hypot(dx, dy) * u.pixel)
angle = (np.arctan2(dy, dx) * u.radian).to(u.deg)
return scale, angle
def __wcs_skycoord_to_pixels(self) -> Tuple[np.ndarray, np.ndarray]:
"""Use the wcs.utils skycoord_to_pixel to derive the pixel positions
Returns:
Tuple[np.ndarray, np.ndarray] -- Pixels coordinate postions of nearby sources
"""
pix = skycoord_to_pixel(self.coords["sky"], self.wcs) * u.pixel
center_pix = skycoord_to_pixel(self.center_coord, self.wcs) * u.pixel
pix = [p - c for p, c in zip(pix, center_pix)]
return pix
def to_pixel(self, wcs, mode='all'):
"""
Convert the aperture to a `CircularAperture` instance in pixel
coordinates.
Parameters
----------
wcs : `~astropy.wcs.WCS`
The WCS transformation to use.
mode : {'all', 'wcs'}, optional
Whether to do the transformation including distortions
(``'all'``; default) or only including only the core WCS
transformation (``'wcs'``).
Returns
-------
aperture : `CircularAperture` object
A `CircularAperture` object.
"""
x, y = skycoord_to_pixel(self.positions, wcs, mode=mode)
if self.r.unit.physical_type == 'angle':
central_pos = SkyCoord([wcs.wcs.crval], frame=self.positions.name,
unit=wcs.wcs.cunit)
xc, yc, scale, angle = skycoord_to_pixel_scale_angle(central_pos,
wcs)
r = (scale * self.r).to(u.pixel).value
else: # pixels
r = self.r.value
pixel_positions = np.array([x, y]).transpose()
return CircularAperture(pixel_positions, r)
def show_image(im: Image, fig=None, title: str = '', pol=0, chan=0, cm='rainbow', components=None):
""" Show an Image with coordinates using matplotlib
:param im:
:param fig:
:param title:
:param pol: Polarisation
:param chan: Channel
:param components: Optional components
:return:
"""
import matplotlib.pyplot as plt
assert isinstance(im, Image), im
if not fig:
fig = plt.figure()
plt.clf()
fig.add_subplot(111, projection=im.wcs.sub(['longitude', 'latitude']))
if len(im.data.shape) == 4:
plt.imshow(numpy.real(im.data[chan, pol, :, :]), origin='lower', cmap=cm)
elif len(im.data.shape) == 2:
plt.imshow(numpy.real(im.data[:, :]), origin='lower', cmap=cm)
plt.xlabel('RA---SIN')
plt.ylabel('DEC--SIN')
plt.title(title)
plt.colorbar()
if components is not None:
for sc in components:
x, y = skycoord_to_pixel(sc.direction, im.wcs, 1, 'wcs')
plt.plot(x, y, marker='+')
return fig
def _world_to_pixel(skycoord, wcs):
"""
Calculate the sky coordinates at the input pixel positions.
Parameters
----------
skycoord : `~astropy.coordinates.SkyCoord`
The sky coordinate(s).
wcs : WCS object or `None`
A world coordinate system (WCS) transformation that supports the
`astropy shared interface for WCS
<https://docs.astropy.org/en/stable/wcs/wcsapi.html>`_ (e.g.
`astropy.wcs.WCS`, `gwcs.wcs.WCS`).
Returns
-------
xpos, ypos : float or array-like
The x and y pixel position(s) at the input sky coordinate(s).
"""
if wcs is None:
return None
try:
return wcs.world_to_pixel(skycoord)
except AttributeError:
if isinstance(wcs, WCS):
# for Astropy < 3.1 WCS support
return skycoord_to_pixel(skycoord, wcs, origin=0)
else:
raise ValueError('Input wcs does not support the shared WCS '
'interface.')
def fit_skycomponent(im: Image, sc: SkyCoord, params={}):
""" Find flux at a given direction, return SkyComponent
:param im:
:type Image:
:param sc:
:type SkyCoord:
:returns: SkyComponent
"""
log_parameters(params)
log.debug(
"find_flux_at_direction: Extracting flux at world coordinates %s" %
str(sc))
w = im.wcs.sub(['longitude', 'latitude'])
pixloc = skycoord_to_pixel(sc, im.wcs, 0, 'wcs')
log.debug(
"find_flux_at_direction: Extracting flux at pixel coordinates %d %d" %
(pixloc[0], pixloc[1]))
flux = im.data[:, :, int(pixloc[1] + 0.5), int(pixloc[0] + 0.5)]
log.debug("find_flux_at_direction: Flux is %s" % flux)
# We also need the frequency values
w = im.wcs.sub(['spectral'])
frequency = w.wcs_pix2world(range(im.data.shape[0]), 0)
return create_skycomponent(direction=sc,
flux=flux,
frequency=frequency,
shape='point')
def test_auto_rotate_systematic(self, angle):
# This is a test to make sure for a number of angles that the corners
# of the image are inside the final WCS but the next pixels outwards are
# not. We test the full 360 range of angles.
angle = np.radians(angle)
pc = np.array([[np.cos(angle), -np.sin(angle)],
[np.sin(angle), np.cos(angle)]])
self.wcs.wcs.pc = pc
wcs, shape = find_optimal_celestial_wcs([(self.array, self.wcs)],
auto_rotate=True)
ny, nx = self.array.shape
xp = np.array([0, 0, nx - 1, nx - 1, -1, -1, nx, nx])
yp = np.array([0, ny - 1, ny - 1, 0, -1, ny, ny, -1])
c = pixel_to_skycoord(xp, yp, self.wcs, origin=0)
xp_final, yp_final = skycoord_to_pixel(c, wcs, origin=0)
ny_final, nx_final = shape
inside = ((xp_final >= -0.5) & (xp_final <= nx_final - 0.5) &
(yp_final >= -0.5) & (yp_final <= ny_final - 0.5))
assert_equal(inside, [1, 1, 1, 1, 0, 0, 0, 0])
def __init__(self, nddata, position, shape):
if isinstance(position, SkyCoord):
if nddata.wcs is None:
raise ValueError('nddata must contain WCS if the input '
'position is a SkyCoord')
x, y = skycoord_to_pixel(position, nddata.wcs, mode='all')
position = (y, x)
data = np.asanyarray(nddata.data)
print(data.shape, shape, position)
slices_large, slices_small = overlap_slices(data.shape, shape,
position)
self.slices_large = slices_large
self.slices_small = slices_small
data = nddata.data[slices_large]
mask = None
uncertainty = None
if nddata.mask is not None:
mask = nddata.mask[slices_large]
if nddata.uncertainty is not None:
uncertainty = nddata.uncertainty[slices_large]
self.nddata = NDData(data, mask=mask, uncertainty=uncertainty)
def generate_pv_line_coordinates(angle, box, wcs, n_points):
"""
This function generates the PV pixel and sky position given
the its PA in degrees.
"""
angle_pvline = np.pi / 180 * (angle + 90)
def y_pv(xp, m, x0, y0):
return m * (xp - x0) + y0
vla4b_sky = SkyCoord(*mf.default_params['vla4b_deg'], unit='deg')
vla4b_pixel = skycoord_to_pixel(vla4b_sky, wcs)
# aframe = vla4b_sky.skyoffset_frame()
# vla4b_offset = vla4b_sky.transform_to(aframe)
x_first, y_first = box[1]
x_last, y_last = box[0]
xs_pixel = np.array([x for x in np.linspace(x_first, x_last, n_points)])
ys_pixel = np.array([
y_pv(
x,
np.tan(angle_pvline),
vla4b_pixel[0],
vla4b_pixel[1],
) for x in xs_pixel
])
xys_sky_PV = np.array(
[pixel_to_skycoord(x, y, wcs) for x, y in zip(xs_pixel, ys_pixel)])
return xys_sky_PV
def make_proposal_boxes(wcs: WCS, catalogue: Table):
"""
Create Faster RCNN proposal boxes for all sources in the image
The sky_coords seems to be swapped x and y on the boxes, so should be swapped here too
:param wcs: WCS of the Radio data, so catalog data can be translated correctly
:param catalogue: Catalogue to query
:return: A Numpy array that holds the information in the correct location
"""
ra_array = np.array(catalogue["ra"], dtype=float)
dec_array = np.array(catalogue["dec"], dtype=float)
sky_coords = SkyCoord(ra_array, dec_array, unit="deg")
# Now have the objects, need to convert those RA and Decs to pixel coordinates
proposals = []
coords = skycoord_to_pixel(sky_coords, wcs, 0)
for index, x in enumerate(coords[0]):
try:
proposals.append(
make_bounding_box(
ra_array[index],
dec_array[index],
wcs=wcs,
class_name="Proposal Box",
)
)
except Exception as e:
print(f"Failed Proposal: {e}")
return proposals
def getSourceVals(RA, DEC, w, hdu, allfreq):
c = SkyCoord(RA, DEC, frame='fk5', unit='deg')
x, y = wcs.skycoord_to_pixel(c, w)
X = np.rint(x)
Y = np.rint(y)
#hdu=pf.open(cube, memmap=True, mode='denywrite')
if Y < 0 or X < 0: #Y > hdu[0].data.shape[1] or X > hdu[0].data.shape[2] or
#print "Source not in image!"
col = []
return col, allfreq
col = hdu[0].data[:, 0, int(Y), int(X)]
#hdu.close()
#col = cube[:,int(Y),int(X)]
flag = np.zeros(col.size)
flag[np.isfinite(col)] = 1
flag[np.abs(col) > 10] = 0
flag[col == 0] = 0
#pdb.set_trace()
col = np.where(is_outlier(col), np.nan, col)
col = np.where(np.isfinite(col), col, np.nan)
col = np.where(col == 0, np.nan, col)
col = np.where(np.abs(col) > 1E15, np.nan, col)
#col=col[flag==1]
#allfreq=allfreq[flag==1]
return col, allfreq
def voronoi_decomposition(im, comps):
"""Construct a Voronoi decomposition of a set of components
The array return contains the index into the Voronoi structure
:param im:
:param comps:
:return: Voronoi structure, vertex image
"""
def voronoi_vertex(vy, vx, vertex_y, vertex_x):
""" Return the nearest Voronoi vertex
:param vy:
:param vx:
:param vertex_y:
:param vertex_x:
:return:
"""
return numpy.argmin(numpy.hypot(vy - vertex_y, vx - vertex_x))
directions = SkyCoord([u.rad * c.direction.ra.rad for c in comps],
[u.rad * c.direction.dec.rad for c in comps])
x, y = skycoord_to_pixel(directions, im.wcs, 0, 'wcs')
points = [(x[i], y[i]) for i, _ in enumerate(x)]
vor = Voronoi(points)
nchan, npol, ny, nx = im.shape
vertex_image = numpy.zeros([ny, nx]).astype('int')
for j in range(ny):
for i in range(nx):
vertex_image[j, i] = voronoi_vertex(j, i, vor.points[:, 1], vor.points[:, 0])
return vor, vertex_image
def test_skycoord_to_pixel(mode):
# Import astropy.coordinates here to avoid circular imports
from astropy.coordinates import SkyCoord
header = get_pkg_data_contents('maps/1904-66_TAN.hdr', encoding='binary')
wcs = WCS(header)
ref = SkyCoord(0.1 * u.deg, -89. * u.deg, frame='icrs')
xp, yp = skycoord_to_pixel(ref, wcs, mode=mode)
# WCS is in FK5 so we need to transform back to ICRS
new = pixel_to_skycoord(xp, yp, wcs, mode=mode).transform_to('icrs')
assert_allclose(new.ra.degree, ref.ra.degree)
assert_allclose(new.dec.degree, ref.dec.degree)
# Make sure you can specify a different class using ``cls`` keyword
class SkyCoord2(SkyCoord):
pass
new2 = pixel_to_skycoord(xp, yp, wcs, mode=mode,
cls=SkyCoord2).transform_to('icrs')
assert new2.__class__ is SkyCoord2
assert_allclose(new2.ra.degree, ref.ra.degree)
assert_allclose(new2.dec.degree, ref.dec.degree)
def test_auto_rotate_systematic(self, angle):
# This is a test to make sure for a number of angles that the corners
# of the image are inside the final WCS but the next pixels outwards are
# not. We test the full 360 range of angles.
angle = np.radians(angle)
pc = np.array([[np.cos(angle), -np.sin(angle)],
[np.sin(angle), np.cos(angle)]])
self.wcs.wcs.pc = pc
wcs, shape = find_optimal_celestial_wcs([(self.array, self.wcs)], auto_rotate=True)
ny, nx = self.array.shape
xp = np.array([0, 0, nx - 1, nx - 1, -1, -1, nx, nx])
yp = np.array([0, ny - 1, ny - 1, 0, -1, ny, ny, -1])
c = pixel_to_skycoord(xp, yp, self.wcs, origin=0)
xp_final, yp_final = skycoord_to_pixel(c, wcs, origin=0)
ny_final, nx_final = shape
inside = ((xp_final >= -0.5) & (xp_final <= nx_final - 0.5) &
(yp_final >= -0.5) & (yp_final <= ny_final - 0.5))
assert_equal(inside, [1, 1, 1, 1, 0, 0, 0, 0])
def to_pixel(self, wcs, mode='all'):
"""
Convert the aperture to a `CircularAperture` instance in pixel
coordinates.
Parameters
----------
wcs : `~astropy.wcs.WCS`
The WCS transformation to use.
mode : {'all', 'wcs'}, optional
Whether to do the transformation including distortions
(``'all'``; default) or only including only the core WCS
transformation (``'wcs'``).
Returns
-------
aperture : `CircularAperture` object
A `CircularAperture` object.
"""
x, y = skycoord_to_pixel(self.positions, wcs, mode=mode)
if self.r.unit.physical_type == 'angle':
central_pos = SkyCoord([wcs.wcs.crval], frame=self.positions.name,
unit=wcs.wcs.cunit)
xc, yc, scale, angle = skycoord_to_pixel_scale_angle(central_pos,
wcs)
r = (scale * self.r).to(u.pixel).value
else: # pixels
r = self.r.value
pixel_positions = np.array([x, y]).transpose()
return CircularAperture(pixel_positions, r)
def to_pixel(self, wcs):
"""
Return a EllipticalAnnulus instance in pixel coordinates.
"""
x, y = skycoord_to_pixel(self.positions, wcs,
mode=skycoord_to_pixel_mode)
central_pos = SkyCoord([wcs.wcs.crval], frame=self.positions.name,
unit=wcs.wcs.cunit)
xc, yc, scale, angle = skycoord_to_pixel_scale_angle(central_pos, wcs)
if self.a_in.unit.physical_type == 'angle':
a_in = (scale * self.a_in).to(u.pixel).value
a_out = (scale * self.a_out).to(u.pixel).value
b_out = (scale * self.b_out).to(u.pixel).value
else:
a_in = self.a_in.value
a_out = self.a_out.value
b_out = self.b_out.value
theta = (angle + self.theta).to(u.radian).value
pixel_positions = np.array([x, y]).transpose()
return EllipticalAnnulus(pixel_positions, a_in, a_out, b_out, theta)
def extract_gaussian_parameters_from_component_catalogue(
pandas_cat,
wcs,
arcsec_per_pixel=1.5,
PA_offset_degree=90,
maj_min_in_arcsec=True,
peak_flux_is_in_mJy=True,
):
# Create skycoords for the center locations of all gaussians
c = SkyCoord(pandas_cat.RA, pandas_cat.DEC, unit="deg")
# transform ra, decs to pixel coordinates
if maj_min_in_arcsec:
deg2arcsec = 1
else:
deg2arcsec = 3600
if peak_flux_is_in_mJy:
mJy2Jy = 1000
else:
mJy2Jy = 1
pixel_locs = skycoord_to_pixel(c, wcs, origin=0, mode="all")
gaussians = [
models.Gaussian2D(
row.Peak_flux / mJy2Jy,
x,
y,
FWHM_to_sigma_for_gaussian(row.Maj * deg2arcsec /
arcsec_per_pixel),
FWHM_to_sigma_for_gaussian(row.Min * deg2arcsec /
arcsec_per_pixel),
theta=np.deg2rad(row.PA + PA_offset_degree),
) for ((irow, row), x,
y) in zip(pandas_cat.iterrows(), pixel_locs[0], pixel_locs[1])
]
return gaussians
def test_skycoord_to_pixel(mode):
# Import astropy.coordinates here to avoid circular imports
from astropy.coordinates import SkyCoord
header = get_pkg_data_contents('data/maps/1904-66_TAN.hdr',
encoding='binary')
wcs = WCS(header)
ref = SkyCoord(0.1 * u.deg, -89. * u.deg, frame='icrs')
xp, yp = skycoord_to_pixel(ref, wcs, mode=mode)
# WCS is in FK5 so we need to transform back to ICRS
new = pixel_to_skycoord(xp, yp, wcs, mode=mode).transform_to('icrs')
assert_allclose(new.ra.degree, ref.ra.degree)
assert_allclose(new.dec.degree, ref.dec.degree)
# Make sure you can specify a different class using ``cls`` keyword
class SkyCoord2(SkyCoord):
pass
new2 = pixel_to_skycoord(xp, yp, wcs, mode=mode,
cls=SkyCoord2).transform_to('icrs')
assert new2.__class__ is SkyCoord2
assert_allclose(new2.ra.degree, ref.ra.degree)
assert_allclose(new2.dec.degree, ref.dec.degree)
def mask_galaxy(image, wcs, Ra, Dec, name, radius):
"""Masks galaxy at Ra, Dec within a radius given in arcminutes
Creates a circular mask centered at a given Ra, Dec. The radius
is given in arcmins. The wcs object is used to convert these inputs
to pixel locations. A pixel scale is also determined. If the object
name is suppled, SESAME is used to find object center. If no active
internet connection is available, center location must be manually
entered, in degrees. If no center coordinates are supplied, (0, 0)
is the default center.
Args:
image(array, required): Image data
wcs: World Coordinte System object
name(str, optional): Name of galaxy or object
Ra(str): Right Ascention
Dec(str): Declination
Radius(float, required): Radius to be masked, in arcminutes
Returns:
masked_img(array): Image which has been masked
mask(boolean array): Mask of the given object"""
# Radius must be given in arcminutes
# Dimentions of the image
dim = (image.shape)
y, x = dim[0], dim[1]
# Finds the center of an object by inputting its name into SESAME
# This requires an active internet connection
# a, b are the coordinates of the center given in pixels
try:
center = SkyCoord.from_name(name)
except Exception:
print("No active internet connection. Manually enter Ra, Dec.")
Ra = Ra
Dec = Dec
center = SkyCoord(Ra, Dec, unit="deg")
c_pix = skycoord_to_pixel(center, wcs)
a, b = c_pix[0], c_pix[1]
print(center)
radius = radius * u.arcmin
# Finds pixel scale using WSC object. The default units can be found by
# unit = header['CUNIT1'], they are degrees by convention
# degrees are converted to arcmins and radius in computed in pixels
scale = proj_plane_pixel_scales(wcs)
pix_scale = scale[0] * u.deg.to(u.arcmin)
print('Image Scale: ' + str(pix_scale) + ' arcmin/pix')
rad_pix = (radius / pix_scale).value
# Indexes each pixel and checks if its is >= radius from center
Y, X = np.ogrid[:y, :x]
dist_from_center = np.sqrt((X - a)**2 + (Y - b)**2)
mask = dist_from_center <= rad_pix
return mask
def main():
files = np.loadtxt("filenames_M8_wcs.txt", dtype='str')
for infile in files:
print infile
ccmapfile = open('Lagoon_2MASS_xy_radec.dat', 'w')
newfile = infile.replace('wcs', 'wcs2')
copyfile(infile, newfile)
coords = np.loadtxt('Lagoon_2MASS_radec_amended.dat', dtype=str)
ra = coords[:, 0]
ra = np.array([float(i) for i in ra])
dec = coords[:, 1]
dec = np.array([float(i) for i in dec])
# open image:
instr = fits.open(infile, mode='readonly', memmap=True)
pixels = instr[0].data[:]
crval1p = instr[0].header['CRVAL1P']
crval2p = instr[0].header['CRVAL2P']
instr.close()
for i in np.arange(len(ra)):
skyposition = SkyCoord(ra[i],
dec[i],
unit=('deg', 'deg'),
frame='icrs')
wcs = WCS(infile)
pixelpos = skycoord_to_pixel(skyposition, wcs=wcs)
columns = str(int(round(pixelpos[0])))
rows = str(int(round(pixelpos[1])))
## Guess at flux:
fluxguess = str(pixels[int(rows), int(columns)])
result = kepprf_AMC.kepprf_AMC(infile,'1',columns,rows,fluxguess,border=1,background='yes',focus='no', \
prfdir='/Users/acody/Data/Kepler',xtol=0.0001,ftol=0.01,verbose=False,logfile='kepprf.log')
newx = result[1] - crval1p + 1
newy = result[2] - crval2p + 1
print >> ccmapfile, newx, newy, ra[i], dec[i]
ccmapfile.close()
# Call ccmap to compute new wcs
iraf.ccmap("Lagoon_2MASS_xy_radec.dat",
"Lagoon_coordfit.db",
images=newfile,
lngunit="degrees",
latunit="degrees",
update="yes",
verbose="no",
interactive="no")
os.remove('Lagoon_2MASS_xy_radec.dat')
os.remove('Lagoon_coordfit.db')
def MakeTiffCut(tiledir, outdir, positions, xs, ys, df, maketiff, makepngs):
logger = logging.getLogger(__name__)
os.makedirs(outdir, exist_ok=True)
imgname = glob.glob(tiledir + '*.tiff')
try:
im = Image.open(imgname[0])
#except IOError as e:
except IndexError as e:
print('No TIFF file found for tile ' + df['TILENAME'][0] + '. Will not create true-color cutout.')
logger.error('MakeTiffCut - No TIFF file found for tile ' + df['TILENAME'][0] + '. Will not create true-color cutout.')
return
# try opening I band FITS (fallback on G, R bands)
hdul = None
for _i in ['i','g','r','z','Y']:
tilename = glob.glob(tiledir+'*_{}.fits.fz'.format(_i))
try:
hdul = fits.open(tilename[0])
except IOError as e:
hdul = None
logger.warning('MakeTiffCut - Could not find master FITS file: ' + tilename)
continue
else:
break
if not hdul:
print('Cannot find a master fits file for this tile.')
logger.error('MakeTiffCut - Cannot find a master fits file for this tile.')
return
w = WCS(hdul['SCI'].header)
pixelscale = utils.proj_plane_pixel_scales(w)
dx = int(0.5 * xs * ARCMIN_TO_DEG / pixelscale[0]) # pixelscale is in degrees (CUNIT)
dy = int(0.5 * ys * ARCMIN_TO_DEG / pixelscale[1])
pixcoords = utils.skycoord_to_pixel(positions, w, origin=0, mode='wcs')
for i in range(len(positions)):
if 'COADD_OBJECT_ID' in df:
filenm = outdir + str(df['COADD_OBJECT_ID'][i])
else:
filenm = outdir + 'x{0}y{1}'.format(df['RA'][i], df['DEC'][i])
#filenm = outdir + 'DESJ' + _DecConverter(df['RA'][0], df['DEC'][0])
left = max(0, pixcoords[0][i] - dx)
upper = max(0, im.size[1] - pixcoords[1][i] - dy)
right = min(pixcoords[0][i] + dx, 10000)
lower = min(im.size[1] - pixcoords[1][i] + dy, 10000)
newimg = im.crop((left, upper, right, lower))
if newimg.size != (2*dx, 2*dy):
logger.info('MakeTiffCut - {} is smaller than user requested. This is likely because the object/coordinate was in close proximity to the edge of a tile.'.format(filenm.split('/')[-1]))
if maketiff:
newimg.save(filenm+'.tiff', format='TIFF')
if makepngs:
newimg.save(filenm+'.png', format='PNG')
logger.info('MakeTiffCut - Tile {} complete.'.format(df['TILENAME'][0]))
def insert_skycomponent_para(im: image_for_para,
sc: Union[Skycomponent, List[Skycomponent]],
insert_method='',
bandwidth=1.0,
support=8) -> image_for_para:
'''
:param im: 被插入的image
:param sc: 插入的skycomponent，可以有多个skycomponent
:param insert_method: 插入方法，四种分别为: Lanczos Sinc PSWF 和 缺省方法
:param bandwidth:
:param support:
:return: 新的image
'''
if type(im) == tuple:
im = im[1]
assert type(im) == image_for_para
support = int(support / bandwidth)
ny, nx = im.shape
if not isinstance(sc, collections.Iterable):
sc = [sc]
for comp in sc:
assert comp.shape == 'Point', "Cannot handle shape %s" % comp.shape
pixloc = skycoord_to_pixel(comp.direction, im.wcs, 1, 'wcs')
if insert_method == "Lanczos":
insert_array_para(im.data,
pixloc[0],
pixloc[1],
comp.flux[im.channel, im.polarisation],
bandwidth,
support,
insert_function=insert_function_L)
elif insert_method == "Sinc":
insert_array_para(im.data,
pixloc[0],
pixloc[1],
comp.flux[im.channel, im.polarisation],
bandwidth,
support,
insert_function=insert_function_sinc)
elif insert_method == "PSWF":
insert_array_para(im.data,
pixloc[0],
pixloc[1],
comp.flux[im.channel, im.polarisation],
bandwidth,
support,
insert_function=insert_function_pswf)
else:
y, x = numpy.round(pixloc[1]).astype('int'), numpy.round(
pixloc[0]).astype('int')
if x >= 0 and x < nx and y >= 0 and y < ny:
im.data[y, x] += comp.flux[im.channel, im.polarisation]
return im
def to_pixel(self, wcs, mode='local', tolerance=None):
if mode != 'local':
raise NotImplementedError
if tolerance is not None:
raise NotImplementedError
x, y = skycoord_to_pixel(self.vertices, wcs)
vertices_pix = PixCoord(x, y)
return PolygonPixelRegion(vertices_pix)
def skytopix(self, sky):
"""
Given a skycoord (or list of skycoords) returns the pixel locations
"""
hdu = self.sci
hdr = hdu.header
wcs, frame = WCS(hdr), hdr['RADESYS'].lower()
pixel = skycoord_to_pixel(sky, wcs)
return pixel
def lm(self, ra, dec):
coord = SkyCoord(ra=ra * u.rad, dec=dec * u.rad)
coord_pixels = utils.skycoord_to_pixel(coords=coord, wcs=self.wcs, origin=0, mode='all')
if np.isnan(np.sum(coord_pixels)):
l, m = -0.0, 0.0
else:
l, m = coord_pixels[self.ra_axis], coord_pixels[self.dec_axis]
l = (l - self._l0) * -self.xscale
m = (m - self._m0) * self.yscale
return l, m
def show_image(im: Image,
fig=None,
title: str = '',
pol=0,
chan=0,
cm='Greys',
components=None,
vmin=None,
vmax=None,
vscale=1.0):
""" Show an Image with coordinates using matplotlib, optionally with components
:param im: Image
:param fig: Matplotlib figure
:param title: String for title of plot
:param pol: Polarisation to show (index)
:param chan: Channel to show (index)
:param components: Optional components to be overlaid
:param vmin: Clip to this minimum
:param vmax: Clip to this maximum
:param vscale: scale max, min by this amount
:return:
"""
import matplotlib.pyplot as plt
assert isinstance(im, Image), im
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, projection=im.wcs.sub([1, 2]))
if len(im.data.shape) == 4:
data_array = numpy.real(im.data[chan, pol, :, :])
else:
data_array = numpy.real(im.data)
if vmax is None:
vmax = vscale * numpy.max(data_array)
if vmin is None:
vmin = vscale * numpy.min(data_array)
cm = ax.imshow(data_array, origin='lower', cmap=cm, vmax=vmax, vmin=vmin)
ax.set_xlabel(im.wcs.wcs.ctype[0])
ax.set_ylabel(im.wcs.wcs.ctype[1])
ax.set_title(title)
fig.colorbar(cm, orientation='vertical', shrink=0.7)
if components is not None:
for sc in components:
x, y = skycoord_to_pixel(sc.direction, im.wcs, 0, 'wcs')
ax.plot(x, y, marker='+', color='red')
return fig
def show_skymodel(sms, psf_width=1.75, cm='Greys', vmax=None, vmin=None):
""" Show a list of SkyModels
:param sms: List of SkyModels
:param psf_width: Width of PSF in pixels
:param cm: matplotlib colormap
:param vmax: Maximum in image display
:param vmin: Minimum in image display
:return:
"""
sp = 1
for ism, sm in enumerate(sms):
plt.clf()
plt.subplot(121, projection=sms[ism].image.wcs.sub([1, 2]))
sp += 1
smodel = copy_image(sms[ism].image)
smodel = insert_skycomponent(smodel, sms[ism].components)
smodel = smooth_image(smodel, psf_width)
if vmax is None:
vmax = numpy.max(smodel.data[0, 0, ...])
if vmin is None:
vmin = numpy.min(smodel.data[0, 0, ...])
plt.imshow(smodel.data[0, 0, ...],
origin='lower',
cmap=cm,
vmax=vmax,
vmin=vmin)
plt.xlabel(sms[ism].image.wcs.wcs.ctype[0])
plt.ylabel(sms[ism].image.wcs.wcs.ctype[1])
plt.title('SkyModel%d' % ism)
components = sms[ism].components
if components is not None:
for sc in components:
x, y = skycoord_to_pixel(sc.direction, sms[ism].image.wcs, 0,
'wcs')
plt.plot(x, y, marker='+', color='red')
gaintable = sms[ism].gaintable
if gaintable is not None:
plt.subplot(122)
sp += 1
phase = numpy.angle(sm.gaintable.gain[:, :, 0, 0, 0])
phase -= phase[:, 0][:, numpy.newaxis]
plt.imshow(phase, origin='lower')
plt.xlabel('Dish/Station')
plt.ylabel('Integration')
plt.show()
def plot_exclusion_mask(self, size=None, **kwargs):
"""Plot exclusion mask for this observation
The plot will be centered at the pointing position
Parameters
----------
size : `~astropy.coordinates.Angle`
Edge length of the plot
"""
size = Angle('5 deg') if size is None else size
ax = self.meta.exclusion.plot(**kwargs)
self._set_ax_limits(ax, size)
point = skycoord_to_pixel(self.meta.pointing, ax.wcs)
ax.scatter(point[0], point[1], s=250, marker="+", color='black')
return ax
def skycoord_to_pixel(coords, wcs, unit='deg'):
"""Transform sky coordinates (ra, dec) to pixel coordinates (x, y) given a wcs.
:param coords: Coordinates. Multiple formats accepted:
- [ra, dec]
- [[ra1, ra2], [dec1, dec2]]
- or a SkyCoord object
:param wcs: an astropy.wcs.WCS object
:return: A list of (x, y) coordinates in pixel units
"""
if not isinstance(coords, SkyCoord):
coords = SkyCoord(coords[0], coords[1], unit=unit)
return utils.skycoord_to_pixel(coords, wcs)
def _to_pixel_params(self, wcs, mode='all'):
"""
Convert the sky aperture parameters to those for a pixel
aperture.
Parameters
----------
wcs : `~astropy.wcs.WCS`
The world coordinate system (WCS) transformation to use.
mode : {'all', 'wcs'}, optional
Whether to do the transformation including distortions
(``'all'``; default) or only including only the core WCS
transformation (``'wcs'``).
Returns
-------
pixel_params : dict
A dictionary of parameters for an equivalent pixel aperture.
"""
pixel_params = {}
x, y = skycoord_to_pixel(self.positions, wcs, mode=mode)
pixel_params['positions'] = np.array([x, y]).transpose()
# The aperture object must have a single value for each shape
# parameter so we must use a single pixel scale for all positions.
# Here, we define the scale at the WCS CRVAL position.
crval = SkyCoord([wcs.wcs.crval], frame=wcs_to_celestial_frame(wcs),
unit=wcs.wcs.cunit)
scale, angle = pixel_scale_angle_at_skycoord(crval, wcs)
params = self._params[:]
theta_key = 'theta'
if theta_key in self._params:
pixel_params[theta_key] = (self.theta + angle).to(u.radian).value
params.remove(theta_key)
param_vals = [getattr(self, param) for param in params]
if param_vals[0].unit.physical_type == 'angle':
for param, param_val in zip(params, param_vals):
pixel_params[param] = (param_val / scale).to(u.pixel).value
else: # pixels
for param, param_val in zip(params, param_vals):
pixel_params[param] = param_val.value
return pixel_params
def test_skycoord_to_pixel_distortions(mode):
# Import astropy.coordinates here to avoid circular imports
from astropy.coordinates import SkyCoord
header = get_pkg_data_filename('data/sip.fits')
wcs = WCS(header)
ref = SkyCoord(202.50 * u.deg, 47.19 * u.deg, frame='icrs')
xp, yp = skycoord_to_pixel(ref, wcs, mode=mode)
# WCS is in FK5 so we need to transform back to ICRS
new = pixel_to_skycoord(xp, yp, wcs, mode=mode).transform_to('icrs')
assert_allclose(new.ra.degree, ref.ra.degree)
assert_allclose(new.dec.degree, ref.dec.degree)
def from_moc(depth_ipix_d, wcs):
# Create a new MOC that do not contain the HEALPix
# cells that are backfacing the projection
depths = [int(depth_str) for depth_str in depth_ipix_d.keys()]
min_depth = min(depths)
max_depth = max(depths)
ipixels = np.asarray(depth_ipix_d[str(min_depth)])
# Split the cells located at the border of the projection
# until at least the depth 7
max_split_depth = max(7, max_depth)
ipix_d = {}
for depth in range(min_depth, max_split_depth + 1):
hp = HEALPix(nside=(1 << depth), order='nested', frame=ICRS())
ipix_boundaries = hp.boundaries_skycoord(ipixels, step=1)
# Projection on the given WCS
xp, yp = skycoord_to_pixel(coords=ipix_boundaries, wcs=wcs)
_, _, frontface_id = backface_culling(xp, yp)
# Get the pixels which are backfacing the projection
backfacing_ipix = ipixels[~frontface_id]
frontface_ipix = ipixels[frontface_id]
depth_str = str(depth)
ipix_d.update({depth_str: frontface_ipix})
next_depth = str(depth + 1)
ipixels = []
if next_depth in depth_ipix_d:
ipixels = depth_ipix_d[next_depth]
for bf_ipix in backfacing_ipix:
child_bf_ipix = bf_ipix << 2
ipixels.extend([child_bf_ipix,
child_bf_ipix + 1,
child_bf_ipix + 2,
child_bf_ipix + 3])
ipixels = np.asarray(ipixels)
return ipix_d
def wcs_skycoord_to_pixel(self, coords):
"""
Convert a set of SkyCoord coordinates into pixels.
Calls `~astropy.wcs.utils.skycoord_to_pixel`, passing ``coords`` to it.
Parameters
----------
coords : `~astropy.coordinates.SkyCoord`
The coordinates to convert.
Returns
-------
xp, yp : `~numpy.ndarray`
The pixel coordinates.
"""
return skycoord_to_pixel(coords=coords, wcs=self.wcs,
origin=_DEFAULT_WCS_ORIGIN,
mode=_DEFAULT_WCS_MODE)
def to_pixel(self, wcs, mode='all'):
"""
Convert the aperture to a `RectangularAnnulus` instance in pixel
coordinates.
Parameters
----------
wcs : `~astropy.wcs.WCS`
The WCS transformation to use.
mode : {'all', 'wcs'}, optional
Whether to do the transformation including distortions
(``'all'``; default) or only including only the core WCS
transformation (``'wcs'``).
Returns
-------
aperture : `RectangularAnnulus` object
A `RectangularAnnulus` object.
"""
x, y = skycoord_to_pixel(self.positions, wcs, mode=mode)
central_pos = SkyCoord([wcs.wcs.crval], frame=self.positions.name,
unit=wcs.wcs.cunit)
xc, yc, scale, angle = skycoord_to_pixel_scale_angle(central_pos, wcs)
if self.w_in.unit.physical_type == 'angle':
w_in = (scale * self.w_in).to(u.pixel).value
w_out = (scale * self.w_out).to(u.pixel).value
h_out = (scale * self.h_out).to(u.pixel).value
else:
# pixels
w_in = self.w_in.value
w_out = self.w_out.value
h_out = self.h_out.value
theta = (angle + self.theta).to(u.radian).value
pixel_positions = np.array([x, y]).transpose()
return RectangularAnnulus(pixel_positions, w_in, w_out, h_out, theta)
def to_pixel(self, wcs):
"""
Convert the aperture to a `CircularAperture` instance in
pixel coordinates.
"""
x, y = skycoord_to_pixel(self.positions, wcs,
mode=skycoord_to_pixel_mode)
if self.r.unit.physical_type == 'angle':
central_pos = SkyCoord([wcs.wcs.crval], frame=self.positions.name,
unit=wcs.wcs.cunit)
xc, yc, scale, angle = skycoord_to_pixel_scale_angle(central_pos,
wcs)
r = (scale * self.r).to(u.pixel).value
else:
r = self.r.value # pixels
pixel_positions = np.array([x, y]).transpose()
return CircularAperture(pixel_positions, r)
def to_pixel(self, wcs):
"""
Return a CircularAnnulus instance in pixel coordinates.
"""
x, y = skycoord_to_pixel(self.positions, wcs,
mode=skycoord_to_pixel_mode)
if self.r_in.unit.physical_type == 'angle':
central_pos = SkyCoord([wcs.wcs.crval], frame=self.positions.name,
unit=wcs.wcs.cunit)
xc, yc, scale, angle = skycoord_to_pixel_scale_angle(central_pos,
wcs)
r_in = (scale * self.r_in).to(u.pixel).value
r_out = (scale * self.r_out).to(u.pixel).value
else: # pixel
r_in = self.r_in.value
r_out = self.r_out.value
pixel_positions = np.array([x, y]).transpose()
return CircularAnnulus(pixel_positions, r_in, r_out)
def linear_offset_coordinates(wcs, center):
'''
return a locally linear offset coordinate system
does the simplest thing possible and assumes no projection distortions
'''
assert isinstance(center, coords.SkyCoord), \
'`center` must by of type `SkyCoord`'
assert center.isscalar, '`center` must have length 1'
# Convert center to pixel coordinates
xp, yp = skycoord_to_pixel(center, wcs)
# Set up new WCS
new_wcs = WCS(naxis=2)
new_wcs.wcs.crpix = xp + 1, yp + 1
new_wcs.wcs.crval = 0., 0.
new_wcs.wcs.cdelt = proj_plane_pixel_scales(wcs)
new_wcs.wcs.ctype = 'XOFFSET', 'YOFFSET'
new_wcs.wcs.cunit = 'deg', 'deg'
return new_wcs
def gcentroid_wcs(im, wcs, guess, **kwargs):
"""Gaussian centroid given sky coordinates.
Parameters
----------
im : ndarray
2D image for centroiding.
wcs : astropy WCS
World coordinate system object.
guess : SkyCoord or tuple of Quantity
Location on which to centroid.
**kwargs
Any ``gcentroid`` keyword arguments.
Returns
-------
cyx : ndarray
Pixel coordinates of the computed center. The lower-left
corner of a pixel is -0.5, -0.5.
c : SkyCoord
World coordinates of the computed center.
"""
if isinstance(guess, coords.SkyCoord):
g = guess
else:
g = coords.SkyCoord(*guess)
gx, gy = np.array(skycoord_to_pixel(g, wcs))
cyx = gcentroid(im, yx=(gy, gx), **kwargs)
c = pixel_to_skycoord(cyx[1], cyx[0], wcs)
return cyx, c
def to_pixel(self, wcs):
"""
Return a `~gammapy.regions.PixCircleRegion`.
Parameters
----------
wcs : `~astropy.wcs.WCS`
WCS object
"""
x, y = skycoord_to_pixel(self.pos, wcs, mode='wcs', origin=1)
pix_radius = self.radius.deg / np.abs(wcs.wcs.cdelt[0])
# TODO understand what is going on here
# from photutils.utils.wcs_helpers import skycoord_to_pixel_scale_angle
# central_pos = SkyCoord([wcs.wcs.crval], frame=self.pos.name, unit=wcs.wcs.cunit)
# xc, yc, scale, angle = skycoord_to_pixel_scale_angle(central_pos, wcs)
# val = (scale * self.radius).to(u.pixel).value
# pix_radius = np.round(val[0],4)
# pix_position = np.array([x, y]).transpose()
return PixCircleRegion((x, y), pix_radius)
def compute_healpix_vertices(depth, ipix, wcs):
path_vertices = np.array([])
codes = np.array([])
depth = int(depth)
step = 1
if depth < 3:
step = 2
hp = HEALPix(order="nested", nside=(1 << depth), frame=ICRS())
ipix_boundaries = hp.boundaries_skycoord(ipix, step=step)
# Projection on the given WCS
xp, yp = skycoord_to_pixel(ipix_boundaries, wcs=wcs)
c1 = np.vstack((xp[:, 0], yp[:, 0])).T
c2 = np.vstack((xp[:, 1], yp[:, 1])).T
c3 = np.vstack((xp[:, 2], yp[:, 2])).T
c4 = np.vstack((xp[:, 3], yp[:, 3])).T
if depth < 3:
c5 = np.vstack((xp[:, 4], yp[:, 4])).T
c6 = np.vstack((xp[:, 5], yp[:, 5])).T
c7 = np.vstack((xp[:, 6], yp[:, 6])).T
c8 = np.vstack((xp[:, 7], yp[:, 7])).T
cells = np.hstack((c1, c2, c3, c4, c5, c6, c7, c8, np.zeros((c1.shape[0], 2))))
path_vertices = cells.reshape((9*c1.shape[0], 2))
single_code = np.array([Path.MOVETO, Path.LINETO, Path.LINETO, Path.LINETO, Path.LINETO, Path.LINETO, Path.LINETO, Path.LINETO, Path.CLOSEPOLY])
else:
cells = np.hstack((c1, c2, c3, c4, np.zeros((c1.shape[0], 2))))
path_vertices = cells.reshape((5*c1.shape[0], 2))
single_code = np.array([Path.MOVETO, Path.LINETO, Path.LINETO, Path.LINETO, Path.CLOSEPOLY])
codes = np.tile(single_code, c1.shape[0])
return path_vertices, codes
def to_pixel(self, wcs):
"""
Return a EllipticalAperture instance in pixel coordinates.
"""
x, y = skycoord_to_pixel(self.positions, wcs,
mode=skycoord_to_pixel_mode)
central_pos = SkyCoord([wcs.wcs.crval], frame=self.positions.name,
unit=wcs.wcs.cunit)
xc, yc, scale, angle = skycoord_to_pixel_scale_angle(central_pos, wcs)
if self.a.unit.physical_type == 'angle':
a = (scale * self.a).to(u.pixel).value
b = (scale * self.b).to(u.pixel).value
else: # pixel
a = self.a.value
b = self.b.value
theta = (angle + self.theta).to(u.radian).value
pixel_positions = np.array([x, y]).transpose()
return EllipticalAperture(pixel_positions, a, b, theta)
def to_pixel(self, wcs):
center_x, center_y = skycoord_to_pixel(self.center, wcs=wcs)
center = PixCoord(center_x, center_y)
return TextPixelRegion(center, self.text, self.meta, self.visual)
def test_fill_acceptance_image():
# create empty image
# odd number of pixels needed for having the center in its own pixel
n_pix_x = 101
n_pix_y = 101
bin_size = Angle(0.1, 'deg')
image = make_empty_image(n_pix_x, n_pix_y, bin_size.degree,
xref=0, yref=0, fill=0,
proj='CAR', coordsys='GAL',
xrefpix=None, yrefpix=None, dtype='float32')
# define center coordinate of the image in wolrd and pixel coordinates
lon = image.header['CRVAL1']
lat = image.header['CRVAL2']
center = SkyCoord(lon, lat, unit='deg', frame='galactic')
# initialize WCS to the header of the image
w = WCS(image.header)
x_center_pix, y_center_pix = skycoord_to_pixel(center, w, origin=0)
# define pixel sizes
# x_pix_size = Angle(abs(image.header['CDELT1']), 'deg')
# y_pix_size = Angle(abs(image.header['CDELT2']), 'deg')
# define radial acceptance and offset angles
# using bin_size for the offset step makes the test comparison easier
offset = Angle(np.arange(0., 30., bin_size.degree), 'deg')
sigma = Angle(1.0, 'deg')
amplitude = 1.
mean = 0.
stddev = sigma.radian
gaus_model = models.Gaussian1D(amplitude, mean, stddev)
acceptance = gaus_model(offset.radian)
# fill acceptance in the image
image = fill_acceptance_image(image.header, center, offset, acceptance)
# test: check points at the offsets where the acceptance is defined
# along the x axis
# define grids of pixel coorinates
xpix_coord_grid, ypix_coord_grid = coordinates(image, world=False)
# calculate pixel offset from center (in world coordinates)
coord = pixel_to_skycoord(xpix_coord_grid, ypix_coord_grid, w, origin=0)
pix_off = coord.separation(center)
# x axis defined in the array positions [y_center_pix,:]
# only interested in semi axis, so [y_center_pix, x_center_pix:]
ix_min = int(x_center_pix)
iy = int(y_center_pix)
pix_off_x_axis = pix_off[iy, ix_min:]
image.data_x_axis = image.data[iy, ix_min:]
# cut offset and acceptance arrays to match image size
# this is only valid if the offset step matches the pixel size
n = pix_off_x_axis.size
acceptance_cut = acceptance[0:n]
# check acceptance of the image:
np.testing.assert_almost_equal(image.data_x_axis, acceptance_cut, decimal=4)
def nddata_cutout2d(nddata, position, size, mode='trim', fill_value=np.nan):
"""
Create a 2D cutout of a `~astropy.nddata.NDData` object.
Specifically, cutouts will made for the ``nddata.data`` and
``nddata.mask`` (if present) arrays. If ``nddata.wcs`` exists, then
it will also be updated.
Note that cutouts will not be made for ``nddata.uncertainty`` (if
present) because they are general objects and not arrays.
Parameters
----------
nddata : `~astropy.nddata.NDData`
The 2D `~astropy.nddata.NDData` from which the cutout is taken.
position : tuple or `~astropy.coordinates.SkyCoord`
The position of the cutout array's center with respect to the
``nddata.data`` array. The position can be specified either as
a ``(x, y)`` tuple of pixel coordinates or a
`~astropy.coordinates.SkyCoord`, in which case ``nddata.wcs``
must exist.
size : int, array-like, `~astropy.units.Quantity`
The size of the cutout array along each axis. If ``size`` is a
scalar number or a scalar `~astropy.units.Quantity`, then a
square cutout of ``size`` will be created. If ``size`` has two
elements, they should be in ``(ny, nx)`` order. Scalar numbers
in ``size`` are assumed to be in units of pixels. ``size`` can
also be a `~astropy.units.Quantity` object or contain
`~astropy.units.Quantity` objects. Such
`~astropy.units.Quantity` objects must be in pixel or angular
units. For all cases, ``size`` will be converted to an integer
number of pixels, rounding the the nearest integer. See the
``mode`` keyword for additional details on the final cutout
size.
mode : {'trim', 'partial', 'strict'}, optional
The mode used for creating the cutout data array. For the
``'partial'`` and ``'trim'`` modes, a partial overlap of the
cutout array and the input ``nddata.data`` array is sufficient.
For the ``'strict'`` mode, the cutout array has to be fully
contained within the ``nddata.data`` array, otherwise an
`~astropy.nddata.utils.PartialOverlapError` is raised. In all
modes, non-overlapping arrays will raise a
`~astropy.nddata.utils.NoOverlapError`. In ``'partial'`` mode,
positions in the cutout array that do not overlap with the
``nddata.data`` array will be filled with ``fill_value``. In
``'trim'`` mode only the overlapping elements are returned, thus
the resulting cutout array may be smaller than the requested
``size``.
fill_value : number, optional
If ``mode='partial'``, the value to fill pixels in the cutout
array that do not overlap with the input ``nddata.data``.
``fill_value`` must have the same ``dtype`` as the input
``nddata.data`` array.
Returns
-------
result : `~astropy.nddata.NDData`
A `~astropy.nddata.NDData` object with cutouts for the data and
mask, if input.
Examples
--------
>>> from astropy.nddata import NDData
>>> import astropy.units as u
>>> from astroimtools import nddata_cutout2d
>>> data = np.random.random((500, 500))
>>> unit = u.electron / u.s
>>> mask = (data > 0.7)
>>> meta = {'exptime': 1234 * u.s}
>>> nddata = NDData(data, mask=mask, unit=unit, meta=meta)
>>> cutout = nddata_cutout2d(nddata, (100, 100), (10, 10))
>>> cutout.data.shape
(10, 10)
>>> cutout.mask.shape
(10, 10)
>>> cutout.unit
Unit("electron / s")
"""
from astropy.nddata.utils import Cutout2D
if not isinstance(nddata, NDData):
raise ValueError('nddata input must be an NDData object')
if isinstance(position, SkyCoord):
if nddata.wcs is None:
raise ValueError('nddata must contain WCS if the input '
'position is a SkyCoord')
position = skycoord_to_pixel(position, nddata.wcs, mode='all')
data_cutout = Cutout2D(np.asanyarray(nddata.data), position, size,
wcs=nddata.wcs, mode=mode, fill_value=fill_value)
# need to create a new NDData instead of copying/replacing
nddata_out = NDData(data_cutout.data, unit=nddata.unit,
uncertainty=nddata.uncertainty, meta=nddata.meta)
if nddata.wcs is not None:
nddata_out.wcs = data_cutout.wcs
if nddata.mask is not None:
mask_cutout = Cutout2D(np.asanyarray(nddata.mask), position, size,
mode=mode, fill_value=fill_value)
nddata_out.mask = mask_cutout.data
return nddata_out
# Todo:voir pour la normalisation normalement il le fait tout seul mais pas sur...
psf_image_SgrA = fill_acceptance_image(header, on.center(), psf_file_SgrA["theta"].to("deg"),
psf_file_SgrA["psf_value"].data, psf_file_SgrA["theta"].to("deg")[-1])
source_center_SgrA = SkyCoord(359.9442, -0.0462, unit='deg', frame="galactic")
# source_center_SgrA = SkyCoord.from_name("SgrA*")
source_center_G0p9 = SkyCoord(0.868, 0.075, unit='deg', frame="galactic")
psf_image_G0p9 = fill_acceptance_image(header, on.center(), psf_file_G0p9["theta"].to("deg"),
psf_file_G0p9["psf_value"].data, psf_file_G0p9["theta"].to("deg")[-1])
psf_image_SgrA.writeto("psf_image_SgrA_" + str(E1) + "_" + str(E2) + ".fits", clobber=True)
psf_image_G0p9.writeto("psf_image_G0p9_" + str(E1) + "_" + str(E2) + ".fits", clobber=True)
load_psf("psf_SgrA", "psf_image_SgrA_" + str(E1) + "_" + str(E2) + ".fits")
load_psf("psf_G0p9", "psf_image_G0p9_" + str(E1) + "_" + str(E2) + ".fits")
# modele gauss pour sgrA centre sur SgrA
mygaus_SgrA = normgauss2dint("SgrA")
mygaus_SgrA.xpos, mygaus_SgrA.ypos = skycoord_to_pixel(source_center_SgrA, on.wcs)
mygaus_SgrA.xpos.val += 0.5
mygaus_SgrA.ypos.val += 0.5
# Modele marge gaussienne a multiplie avec CS centre sur SgrA
large_gaus = Gauss2D("Gauss_to_CS")
large_gaus.xpos, large_gaus.ypos = skycoord_to_pixel(source_center_SgrA, on.wcs)
large_gaus.fwhm = 100
central_gauss = Gauss2D("central_gauss")
central_gauss.xpos, central_gauss.ypos = skycoord_to_pixel(source_center_SgrA, on.wcs)
central_gauss.fwhm = 100
# modele gauss pour G0p9 centre sur G0p9
mygaus_G0p9 = normgauss2dint("G0p9")
mygaus_G0p9.xpos, mygaus_G0p9.ypos = skycoord_to_pixel(source_center_G0p9, on.wcs)
mygaus_G0p9.xpos.val += 0.5
mygaus_G0p9.ypos.val += 0.5
def to_pixel(self, wcs):
center_x, center_y = skycoord_to_pixel(self.center, wcs=wcs)
center = PixCoord(center_x, center_y)
return PointPixelRegion(center)
def __init__(self, data, position, size, wcs=None, mode='trim',
fill_value=np.nan, copy=False):
"""
Parameters
----------
data : `~numpy.ndarray`
The 2D data array from which to extract the cutout array.
position : tuple or `~astropy.coordinates.SkyCoord`
The position of the cutout array's center with respect to
the ``data`` array. The position can be specified either as
a ``(x, y)`` tuple of pixel coordinates or a
`~astropy.coordinates.SkyCoord`, in which case ``wcs`` is a
required input.
size : int, array-like, `~astropy.units.Quantity`
The size of the cutout array along each axis. If ``size``
is a scalar number or a scalar `~astropy.units.Quantity`,
then a square cutout of ``size`` will be created. If
``size`` has two elements, they should be in ``(ny, nx)``
order. Scalar numbers in ``size`` are assumed to be in
units of pixels. ``size`` can also be a
`~astropy.units.Quantity` object or contain
`~astropy.units.Quantity` objects. Such
`~astropy.units.Quantity` objects must be in pixel or
angular units. For all cases, ``size`` will be converted to
an integer number of pixels, rounding the the nearest
integer. See the ``mode`` keyword for additional details on
the final cutout size.
.. note::
If ``size`` is in angular units, the cutout size is
converted to pixels using the pixel scales along each
axis of the image at the ``CRPIX`` location. Projection
and other non-linear distortions are not taken into
account.
wcs : `~astropy.wcs.WCS`, optional
A WCS object associated with the input ``data`` array. If
``wcs`` is not `None`, then the returned cutout object will
contain a copy of the updated WCS for the cutout data array.
mode : {'trim', 'partial', 'strict'}, optional
The mode used for creating the cutout data array. For the
``'partial'`` and ``'trim'`` modes, a partial overlap of the
cutout array and the input ``data`` array is sufficient.
For the ``'strict'`` mode, the cutout array has to be fully
contained within the ``data`` array, otherwise an
`~astropy.nddata.utils.PartialOverlapError` is raised. In
all modes, non-overlapping arrays will raise a
`~astropy.nddata.utils.NoOverlapError`. In ``'partial'``
mode, positions in the cutout array that do not overlap with
the ``data`` array will be filled with ``fill_value``. In
``'trim'`` mode only the overlapping elements are returned,
thus the resulting cutout array may be smaller than the
requested ``shape``.
fill_value : number, optional
If ``mode='partial'``, the value to fill pixels in the
cutout array that do not overlap with the input ``data``.
``fill_value`` must have the same ``dtype`` as the input
``data`` array.
copy : bool, optional
If `False` (default), then the cutout data will be a view
into the original ``data`` array. If `True`, then the
cutout data will hold a copy of the original ``data`` array.
Returns
-------
result : `~astropy.nddata.utils.Cutout2D`
A cutout object containing the 2D cutout data array and the
updated WCS, if ``wcs`` is input.
Examples
--------
>>> import numpy as np
>>> from astropy.nddata.utils import Cutout2D
>>> from astropy import units as u
>>> data = np.arange(20.).reshape(5, 4)
>>> cutout1 = Cutout2D(data, (2, 2), (3, 3))
>>> print(cutout1.data)
[[ 5. 6. 7.]
[ 9. 10. 11.]
[ 13. 14. 15.]]
>>> print(cutout1.center_original)
(2.0, 2.0)
>>> print(cutout1.center_cutout)
(1.0, 1.0)
>>> print(cutout1.origin_original)
(1, 1)
>>> cutout2 = Cutout2D(data, (2, 2), 3)
>>> print(cutout2.data)
[[ 5. 6. 7.]
[ 9. 10. 11.]
[ 13. 14. 15.]]
>>> size = u.Quantity([3, 3], u.pixel)
>>> cutout3 = Cutout2D(data, (0, 0), size)
>>> print(cutout3.data)
[[ 0. 1.]
[ 4. 5.]]
>>> cutout4 = Cutout2D(data, (0, 0), (3 * u.pixel, 3))
>>> print(cutout4.data)
[[ 0. 1.]
[ 4. 5.]]
>>> cutout5 = Cutout2D(data, (0, 0), (3, 3), mode='partial')
>>> print(cutout5.data)
[[ nan nan nan]
[ nan 0. 1.]
[ nan 4. 5.]]
"""
if isinstance(position, SkyCoord):
if wcs is None:
raise ValueError('wcs must be input if position is a '
'SkyCoord')
position = skycoord_to_pixel(position, wcs, mode='all') # (x, y)
if np.isscalar(size):
size = np.repeat(size, 2)
# special handling for a scalar Quantity
if isinstance(size, u.Quantity):
size = np.atleast_1d(size)
if len(size) == 1:
size = np.repeat(size, 2)
if len(size) > 2:
raise ValueError('size must have at most two elements')
shape = np.zeros(2).astype(int)
pixel_scales = None
# ``size`` can have a mixture of int and Quantity (and even units),
# so evaluate each axis separately
for axis, side in enumerate(size):
if not isinstance(side, u.Quantity):
shape[axis] = np.int(np.round(size[axis])) # pixels
else:
if side.unit == u.pixel:
shape[axis] = np.int(np.round(side.value))
elif side.unit.physical_type == 'angle':
if wcs is None:
raise ValueError('wcs must be input if any element '
'of size has angular units')
if pixel_scales is None:
pixel_scales = u.Quantity(
proj_plane_pixel_scales(wcs), wcs.wcs.cunit[axis])
shape[axis] = np.int(np.round(
(side / pixel_scales[axis]).decompose()))
else:
raise ValueError('shape can contain Quantities with only '
'pixel or angular units')
data = np.asanyarray(data)
# reverse position because extract_array and overlap_slices
# use (y, x), but keep the input position
pos_yx = position[::-1]
cutout_data, input_position_cutout = extract_array(
data, tuple(shape), pos_yx, mode=mode, fill_value=fill_value,
return_position=True)
if copy:
cutout_data = np.copy(cutout_data)
self.data = cutout_data
self.input_position_cutout = input_position_cutout[::-1] # (x, y)
slices_original, slices_cutout = overlap_slices(
data.shape, shape, pos_yx, mode=mode)
self.slices_original = slices_original
self.slices_cutout = slices_cutout
self.shape = self.data.shape
self.input_position_original = position
self.shape_input = shape
((self.xmin_original, self.xmax_original),
(self.ymin_original, self.ymax_original)) = self.bbox_original
((self.xmin_cutout, self.xmax_cutout),
(self.ymin_cutout, self.ymax_cutout)) = self.bbox_cutout
# the true origin pixel of the cutout array, including any
# filled cutout values
self._origin_original_true = (
self.origin_original[0] - self.slices_cutout[1].start,
self.origin_original[1] - self.slices_cutout[0].start)
if wcs is not None:
self.wcs = deepcopy(wcs)
self.wcs.wcs.crpix -= self._origin_original_true
else:
self.wcs = None
def listpixels(data, position, shape, subarray_indices=False, wcs=None):
"""
Return a `~astropy.table.Table` listing the ``(y, x)`` positions and
``data`` values for a subarray.
Given a position of the center of the subarray, with respect to the
large array, the array indices and values are returned. This
function takes care of the correct behavior at the boundaries, where
the small array is appropriately trimmed.
Parameters
----------
data : array-like
The input data.
position : tuple (int) or `~astropy.coordinates.SkyCoord`
The position of the subarray center with respect to the data
array. The position can be specified either as an integer ``(y,
x)`` tuple of pixel coordinates or a
`~astropy.coordinates.SkyCoord`, in which case ``wcs`` is a
required input.
shape : tuple (int)
The integer shape (``(ny, nx)``) of the subarray.
subarray_indices : bool, optional
If `True` then the returned positions are relative to the small
subarray. If `False` (default) then the returned positions are
relative to the ``data`` array.
wcs : `~astropy.wcs.WCS`, optional
The WCS transformation to use if ``position`` is a
`~astropy.coordinates.SkyCoord`.
Returns
-------
table : `~astropy.table.Table`
A table containing the ``x`` and ``y`` positions and data
values.
Notes
-----
This function is decorated with `~astropy.nddata.support_nddata` and
thus supports `~astropy.nddata.NDData` objects as input.
Examples
--------
>>> import numpy as np
>>> from astroimtools import listpixels
>>> np.random.seed(12345)
>>> data = np.random.random((25, 25))
>>> tbl = listpixels(data, (8, 11), (3, 3))
>>> for col in tbl.colnames:
... tbl[col].info.format = '%.8g' # for consistent table output
>>> tbl.pprint(max_lines=-1)
x y value
--- --- -----------
10 7 0.75857204
11 7 0.069529666
12 7 0.70547344
10 8 0.8406625
11 8 0.46931469
12 8 0.56264343
10 9 0.034131584
11 9 0.23049655
12 9 0.22835371
"""
if isinstance(position, SkyCoord):
if wcs is None:
raise ValueError('wcs must be input if positions is a SkyCoord')
x, y = skycoord_to_pixel(position, wcs, mode='all')
position = (y, x)
data = np.asanyarray(data)
slices_large, slices_small = overlap_slices(data.shape, shape, position)
slices = slices_large
yy, xx = np.mgrid[slices]
values = data[yy, xx]
if subarray_indices:
slices = slices_small
yy, xx = np.mgrid[slices]
tbl = Table()
tbl['x'] = xx.ravel()
tbl['y'] = yy.ravel()
tbl['value'] = values.ravel()
return tbl
def __init__(self, data, position, size, wcs=None, mode='trim',
fill_value=np.nan, copy=False):
if isinstance(position, SkyCoord):
if wcs is None:
raise ValueError('wcs must be input if position is a '
'SkyCoord')
position = skycoord_to_pixel(position, wcs, mode='all') # (x, y)
if np.isscalar(size):
size = np.repeat(size, 2)
# special handling for a scalar Quantity
if isinstance(size, u.Quantity):
size = np.atleast_1d(size)
if len(size) == 1:
size = np.repeat(size, 2)
if len(size) > 2:
raise ValueError('size must have at most two elements')
shape = np.zeros(2).astype(int)
pixel_scales = None
# ``size`` can have a mixture of int and Quantity (and even units),
# so evaluate each axis separately
for axis, side in enumerate(size):
if not isinstance(side, u.Quantity):
shape[axis] = int(np.round(size[axis])) # pixels
else:
if side.unit == u.pixel:
shape[axis] = int(np.round(side.value))
elif side.unit.physical_type == 'angle':
if wcs is None:
raise ValueError('wcs must be input if any element '
'of size has angular units')
if pixel_scales is None:
pixel_scales = u.Quantity(
proj_plane_pixel_scales(wcs), wcs.wcs.cunit[axis])
shape[axis] = int(np.round(
(side / pixel_scales[axis]).decompose()))
else:
raise ValueError('shape can contain Quantities with only '
'pixel or angular units')
data = np.asanyarray(data)
# reverse position because extract_array and overlap_slices
# use (y, x), but keep the input position
pos_yx = position[::-1]
cutout_data, input_position_cutout = extract_array(
data, tuple(shape), pos_yx, mode=mode, fill_value=fill_value,
return_position=True)
if copy:
cutout_data = np.copy(cutout_data)
self.data = cutout_data
self.input_position_cutout = input_position_cutout[::-1] # (x, y)
slices_original, slices_cutout = overlap_slices(
data.shape, shape, pos_yx, mode=mode)
self.slices_original = slices_original
self.slices_cutout = slices_cutout
self.shape = self.data.shape
self.input_position_original = position
self.shape_input = shape
((self.ymin_original, self.ymax_original),
(self.xmin_original, self.xmax_original)) = self.bbox_original
((self.ymin_cutout, self.ymax_cutout),
(self.xmin_cutout, self.xmax_cutout)) = self.bbox_cutout
# the true origin pixel of the cutout array, including any
# filled cutout values
self._origin_original_true = (
self.origin_original[0] - self.slices_cutout[1].start,
self.origin_original[1] - self.slices_cutout[0].start)
if wcs is not None:
self.wcs = deepcopy(wcs)
self.wcs.wcs.crpix -= self._origin_original_true
self.wcs.array_shape = self.data.shape
if wcs.sip is not None:
self.wcs.sip = Sip(wcs.sip.a, wcs.sip.b,
wcs.sip.ap, wcs.sip.bp,
wcs.sip.crpix - self._origin_original_true)
else:
self.wcs = None
