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 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_loopback(to_frame):
xyz = CartesianRepresentation(1, 2, 3) * u.pc
from_coo = Galactocentric(xyz)
explicit_coo = from_coo.transform_to(ICRS()).transform_to(to_frame)
implicit_coo = from_coo.transform_to(to_frame)
# Confirm that the explicit transformation changes the position
assert not allclose(
explicit_coo.cartesian.xyz, from_coo.cartesian.xyz, rtol=1e-10)
# Confirm that the loopback matches the explicit transformation
assert allclose(explicit_coo.cartesian.xyz,
implicit_coo.cartesian.xyz,
rtol=1e-10)
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
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)
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)
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])
# 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
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():
# 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
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)
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)
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])
# 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
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])
from_coo.cartesian.xyz,
rtol=1e-10)
assert not allclose(
explicit_coo.velocity.d_xyz, from_coo.velocity.d_xyz, rtol=1e-10)
# Confirm that the loopback matches the explicit transformation
assert allclose(explicit_coo.cartesian.xyz,
implicit_coo.cartesian.xyz,
rtol=1e-10)
assert allclose(explicit_coo.velocity.d_xyz,
implicit_coo.velocity.d_xyz,
rtol=1e-10)
@pytest.mark.parametrize('to_frame', [
Galactocentric(galcen_coord=ICRS(300 * u.deg, -30 * u.deg)),
Galactocentric(galcen_distance=10 * u.kpc),
Galactocentric(z_sun=10 * u.pc),
Galactocentric(roll=1 * u.deg)
])
def test_galactocentric_loopback(to_frame):
xyz = CartesianRepresentation(1, 2, 3) * u.pc
from_coo = Galactocentric(xyz)
explicit_coo = from_coo.transform_to(ICRS()).transform_to(to_frame)
implicit_coo = from_coo.transform_to(to_frame)
# Confirm that the explicit transformation changes the position
assert not allclose(
explicit_coo.cartesian.xyz, from_coo.cartesian.xyz, rtol=1e-10)
