def test_galactocentric_references(reset_galactocentric_defaults):
# references in the "scientific paper"-sense
from astropy.coordinates import (Galactocentric,
galactocentric_frame_defaults)
with galactocentric_frame_defaults.set('pre-v4.0'):
galcen_pre40 = Galactocentric()
for k in galcen_pre40.get_frame_attr_names():
if k == 'roll': # no reference for this parameter
continue
assert k in galcen_pre40.frame_attribute_references
with galactocentric_frame_defaults.set('v4.0'):
galcen_40 = Galactocentric()
for k in galcen_40.get_frame_attr_names():
if k == 'roll': # no reference for this parameter
continue
assert k in galcen_40.frame_attribute_references
with galactocentric_frame_defaults.set('v4.0'):
galcen_custom = Galactocentric(z_sun=15*u.pc)
for k in galcen_custom.get_frame_attr_names():
if k == 'roll': # no reference for this parameter
continue
if k == 'z_sun':
assert k not in galcen_custom.frame_attribute_references
else:
assert k in galcen_custom.frame_attribute_references
def test_galactocentric():
# when z_sun=0, transformation should be very similar to Galactic
icrs_coord = ICRS(ra=np.linspace(0, 360, 10) * u.deg,
dec=np.linspace(-90, 90, 10) * u.deg,
distance=1. * u.kpc)
g_xyz = icrs_coord.transform_to(Galactic).cartesian.xyz
with galactocentric_frame_defaults.set('pre-v4.0'):
gc_xyz = icrs_coord.transform_to(Galactocentric(z_sun=0 *
u.kpc)).cartesian.xyz
diff = np.abs(g_xyz - gc_xyz)
assert allclose(diff[0], 8.3 * u.kpc, atol=1E-5 * u.kpc)
assert allclose(diff[1:], 0 * u.kpc, atol=1E-5 * u.kpc)
# generate some test coordinates
g = Galactic(l=[0, 0, 45, 315] * u.deg,
b=[-45, 45, 0, 0] * u.deg,
distance=[np.sqrt(2)] * 4 * u.kpc)
with galactocentric_frame_defaults.set('pre-v4.0'):
xyz = g.transform_to(
Galactocentric(galcen_distance=1. * u.kpc,
z_sun=0. * u.pc)).cartesian.xyz
true_xyz = np.array([[0, 0, -1.], [0, 0, 1], [0, 1, 0], [0, -1, 0]
]).T * u.kpc
assert allclose(xyz.to(u.kpc), true_xyz.to(u.kpc), atol=1E-5 * u.kpc)
# check that ND arrays work
# from Galactocentric to Galactic
x = np.linspace(-10., 10., 100) * u.kpc
y = np.linspace(-10., 10., 100) * u.kpc
z = np.zeros_like(x)
# from Galactic to Galactocentric
l = np.linspace(15, 30., 100) * u.deg
b = np.linspace(-10., 10., 100) * u.deg
d = np.ones_like(l.value) * u.kpc
with galactocentric_frame_defaults.set('latest'):
g1 = Galactocentric(x=x, y=y, z=z)
g2 = Galactocentric(x=x.reshape(100, 1, 1),
y=y.reshape(100, 1, 1),
z=z.reshape(100, 1, 1))
g1t = g1.transform_to(Galactic)
g2t = g2.transform_to(Galactic)
assert_allclose(g1t.cartesian.xyz, g2t.cartesian.xyz[:, :, 0, 0])
g1 = Galactic(l=l, b=b, distance=d)
g2 = Galactic(l=l.reshape(100, 1, 1),
b=b.reshape(100, 1, 1),
distance=d.reshape(100, 1, 1))
g1t = g1.transform_to(Galactocentric)
g2t = g2.transform_to(Galactocentric)
np.testing.assert_almost_equal(g1t.cartesian.xyz.value,
g2t.cartesian.xyz.value[:, :, 0, 0])
def test_galactocentric_defaults(reset_galactocentric_defaults):
from astropy.coordinates import (Galactocentric,
galactocentric_frame_defaults,
BaseCoordinateFrame,
CartesianDifferential)
with galactocentric_frame_defaults.set('pre-v4.0'):
galcen_pre40 = Galactocentric()
with galactocentric_frame_defaults.set('v4.0'):
galcen_40 = Galactocentric()
with galactocentric_frame_defaults.set('latest'):
galcen_latest = Galactocentric()
# parameters that changed
assert not u.allclose(galcen_pre40.galcen_distance,
galcen_40.galcen_distance)
assert not u.allclose(galcen_pre40.z_sun, galcen_40.z_sun)
for k in galcen_40.get_frame_attr_names():
if isinstance(getattr(galcen_40, k), BaseCoordinateFrame):
continue # skip coordinate comparison...
elif isinstance(getattr(galcen_40, k), CartesianDifferential):
assert u.allclose(getattr(galcen_40, k).d_xyz,
getattr(galcen_latest, k).d_xyz)
else:
assert getattr(galcen_40, k) == getattr(galcen_latest, k)
def test_api():
# transform observed Barycentric velocities to full-space Galactocentric
with galactocentric_frame_defaults.set('latest'):
gc_frame = Galactocentric()
icrs = ICRS(ra=151. * u.deg,
dec=-16 * u.deg,
distance=101 * u.pc,
pm_ra_cosdec=21 * u.mas / u.yr,
pm_dec=-71 * u.mas / u.yr,
radial_velocity=71 * u.km / u.s)
icrs.transform_to(gc_frame)
# transform a set of ICRS proper motions to Galactic
icrs = ICRS(ra=151. * u.deg,
dec=-16 * u.deg,
pm_ra_cosdec=21 * u.mas / u.yr,
pm_dec=-71 * u.mas / u.yr)
icrs.transform_to(Galactic)
# transform a Barycentric RV to a GSR RV
icrs = ICRS(ra=151. * u.deg,
dec=-16 * u.deg,
distance=1. * u.pc,
pm_ra_cosdec=0 * u.mas / u.yr,
pm_dec=0 * u.mas / u.yr,
radial_velocity=71 * u.km / u.s)
icrs.transform_to(Galactocentric)
def backwards(self, l_deg, b_deg, d_kpc):
with galactocentric_frame_defaults.set('pre-v4.0'):
gal = Galactic(l=l_deg * u.deg,
b=b_deg * u.deg,
distance=d_kpc * u.kpc).transform_to(Galactocentric)
return gal.x.to(u.kpc).value, gal.y.to(u.kpc).value, gal.z.to(
u.kpc).value
def test_plot_coord_3d_transform(self):
wcs = WCS(self.msx_header)
with galactocentric_frame_defaults.set('latest'):
coord = SkyCoord(0 * u.kpc, 0 * u.kpc, 0 * u.kpc, frame='galactocentric')
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, projection=wcs)
point, = ax.plot_coord(coord, 'ro')
np.testing.assert_allclose(point.get_xydata()[0], [0, 0], atol=1e-4)
def test_frame_affinetransform(kwargs, expect_success):
"""There are already tests in test_transformations.py that check that
an AffineTransform fails without full-space data, but this just checks that
things work as expected at the frame level as well.
"""
with galactocentric_frame_defaults.set('latest'):
icrs = ICRS(**kwargs)
if expect_success:
_ = icrs.transform_to(Galactocentric)
else:
with pytest.raises(ConvertError):
icrs.transform_to(Galactocentric)
def test_galactocentric_default_warning(reset_galactocentric_defaults):
from astropy.coordinates import (Galactocentric,
galactocentric_frame_defaults)
# Make sure a warning is thrown if the frame is created with no args
with pytest.warns(AstropyDeprecationWarning,
match=r"In v4\.1 and later versions"):
Galactocentric()
# Throw a warning even if only a subset of args are specified
with pytest.warns(AstropyDeprecationWarning,
match=r"In v4\.1 and later versions"):
Galactocentric(galcen_distance=8.2*u.kpc)
# No warning if using the latest parameter set:
with galactocentric_frame_defaults.set('latest'):
Galactocentric()
def test_galactocentric_default_warning(reset_galactocentric_defaults):
from astropy.coordinates import (Galactocentric,
galactocentric_frame_defaults)
# Note: this is necessary because the doctests may alter the state of the
# class globally and simultaneously when the tests are run in parallel
# reset_galactocentric_defaults()
# Make sure a warning is thrown if the frame is created with no args
with pytest.warns(AstropyDeprecationWarning,
match=r"In v4\.1 and later versions"):
Galactocentric()
# Throw a warning even if only a subset of args are specified
with pytest.warns(AstropyDeprecationWarning,
match=r"In v4\.1 and later versions"):
Galactocentric(galcen_distance=8.2 * u.kpc)
# No warning if using the latest parameter set:
with galactocentric_frame_defaults.set('latest'):
Galactocentric()
def test_xyz_to_lbr():
x,y,z = pygedm.convert_lbr_to_xyz(0, 0, 0, method='ymw16')
assert x == 0
assert y == 8300 * u.pc
assert z == 6 * u.pc
x,y,z = pygedm.convert_lbr_to_xyz(0, 0, 0, method='ne2001')
assert x == 0
assert y == 8500 * u.pc
assert z == 0
# Who even knows where the centre of the Galaxy is?
# https://docs.astropy.org/en/stable/api/astropy.coordinates.galactocentric_frame_defaults.html
from astropy.coordinates import galactocentric_frame_defaults
_ = galactocentric_frame_defaults.set('v4.0')
x,y,z = pygedm.convert_lbr_to_xyz(0, 0, 0, method='astropy')
assert np.isclose(x.to('pc').value, -1 * Galactocentric().galcen_distance.to('pc').value)
assert y == 0
assert np.isclose(z.to('pc').value, Galactocentric().z_sun.to('pc').value)
x,y,z = pygedm.convert_lbr_to_xyz(Angle(0, unit='degree'), Angle(0, unit='rad'), 0 * u.pc, method='ymw16')
assert x == 0
assert y == 8300 * u.pc
assert z == 6 * u.pc
def forwards(self, x_kpc, y_kpc, z_kpc):
with galactocentric_frame_defaults.set('pre-v4.0'):
gal = Galactocentric(x=x_kpc * u.kpc,
y=y_kpc * u.kpc,
z=z_kpc * u.kpc).transform_to(Galactic)
return gal.l.degree, gal.b.degree, gal.distance.to(u.kpc).value
