Python builtin_frames.ICRS类代码示例

def test_altaz_diffs():
    time = Time('J2015') + np.linspace(-1, 1, 1000)*u.day
    loc = get_builtin_sites()['greenwich']
    aa = AltAz(obstime=time, location=loc)

    icoo = ICRS(np.zeros_like(time)*u.deg, 10*u.deg, 100*u.au,
                pm_ra_cosdec=np.zeros_like(time)*u.marcsec/u.yr,
                pm_dec=0*u.marcsec/u.yr,
                radial_velocity=0*u.km/u.s)

    acoo = icoo.transform_to(aa)

    # Make sure the change in radial velocity over ~2 days isn't too much
    # more than the rotation speed of the Earth - some excess is expected
    # because the orbit also shifts the RV, but it should be pretty small
    # over this short a time.
    assert np.ptp(acoo.radial_velocity)/2 < (2*np.pi*constants.R_earth/u.day)*1.2  # MAGIC NUMBER

    cdiff = acoo.data.differentials['s'].represent_as(CartesianDifferential,
                                                    acoo.data)

    # The "total" velocity should be > c, because the *tangential* velocity
    # isn't a True velocity, but rather an induced velocity due to the Earth's
    # rotation at a distance of 100 AU
    assert np.all(np.sum(cdiff.d_xyz**2, axis=0)**0.5 > constants.c)

def test_skyoffset_functional_ra():
    # we do the 12)[1:-1] business because sometimes machine precision issues
    # lead to results that are either ~0 or ~360, which mucks up the final
    # comparison and leads to spurious failures.  So this just avoids that by
    # staying away from the edges
    input_ra = np.linspace(0, 360, 12)[1:-1]
    input_dec = np.linspace(-90, 90, 12)[1:-1]
    icrs_coord = ICRS(ra=input_ra*u.deg,
                      dec=input_dec*u.deg,
                      distance=1.*u.kpc)

    for ra in np.linspace(0, 360, 24):
        # expected rotation
        expected = ICRS(ra=np.linspace(0-ra, 360-ra, 12)[1:-1]*u.deg,
                        dec=np.linspace(-90, 90, 12)[1:-1]*u.deg,
                        distance=1.*u.kpc)
        expected_xyz = expected.cartesian.xyz

        # actual transformation to the frame
        skyoffset_frame = SkyOffsetFrame(origin=ICRS(ra*u.deg, 0*u.deg))
        actual = icrs_coord.transform_to(skyoffset_frame)
        actual_xyz = actual.cartesian.xyz

        # back to ICRS
        roundtrip = actual.transform_to(ICRS)
        roundtrip_xyz = roundtrip.cartesian.xyz

        # Verify
        assert_allclose(actual_xyz, expected_xyz, atol=1E-5*u.kpc)
        assert_allclose(icrs_coord.ra, roundtrip.ra, atol=1E-5*u.deg)
        assert_allclose(icrs_coord.dec, roundtrip.dec, atol=1E-5*u.deg)
        assert_allclose(icrs_coord.distance, roundtrip.distance, atol=1E-5*u.kpc)

def test_gcrs_diffs():
    time = Time('J2017')
    gf = GCRS(obstime=time)
    sung = get_sun(time)  # should have very little vhelio

    # qtr-year off sun location should be the direction of ~ maximal vhelio
    qtrsung = get_sun(time-.25*u.year)

    # now we use those essentially as directions where the velocities should
    # be either maximal or minimal - with or perpendiculat to Earh's orbit
    msungr = CartesianRepresentation(-sung.cartesian.xyz).represent_as(SphericalRepresentation)
    suni = ICRS(ra=msungr.lon, dec=msungr.lat, distance=100*u.au,
                pm_ra_cosdec=0*u.marcsec/u.yr, pm_dec=0*u.marcsec/u.yr,
                radial_velocity=0*u.km/u.s)
    qtrsuni = ICRS(ra=qtrsung.ra, dec=qtrsung.dec, distance=100*u.au,
                   pm_ra_cosdec=0*u.marcsec/u.yr, pm_dec=0*u.marcsec/u.yr,
                   radial_velocity=0*u.km/u.s)

    # Now we transform those parallel- and perpendicular-to Earth's orbit
    # directions to GCRS, which should shift the velocity to either include
    # the Earth's velocity vector, or not (for parallel and perpendicular,
    # respectively).
    sung = suni.transform_to(gf)
    qtrsung = qtrsuni.transform_to(gf)

    # should be high along the ecliptic-not-sun sun axis and
    # low along the sun axis
    assert np.abs(qtrsung.radial_velocity) > 30*u.km/u.s
    assert np.abs(qtrsung.radial_velocity) < 40*u.km/u.s
    assert np.abs(sung.radial_velocity) < 1*u.km/u.s

    suni2 = sung.transform_to(ICRS)
    assert np.all(np.abs(suni2.data.differentials['s'].d_xyz) < 3e-5*u.km/u.s)
    qtrisun2 = qtrsung.transform_to(ICRS)
    assert np.all(np.abs(qtrisun2.data.differentials['s'].d_xyz) < 3e-5*u.km/u.s)

def test_create_data_frames():
    from astropy.coordinates.builtin_frames import ICRS

    # from repr
    i1 = ICRS(r.SphericalRepresentation(1*u.deg, 2*u.deg, 3*u.kpc))
    i2 = ICRS(r.UnitSphericalRepresentation(lon=1*u.deg, lat=2*u.deg))

    # from preferred name
    i3 = ICRS(ra=1*u.deg, dec=2*u.deg, distance=3*u.kpc)
    i4 = ICRS(ra=1*u.deg, dec=2*u.deg)

    assert i1.data.lat == i3.data.lat
    assert i1.data.lon == i3.data.lon
    assert i1.data.distance == i3.data.distance

    assert i2.data.lat == i4.data.lat
    assert i2.data.lon == i4.data.lon

    # now make sure the preferred names work as properties
    assert_allclose(i1.ra, i3.ra)
    assert_allclose(i2.ra, i4.ra)
    assert_allclose(i1.distance, i3.distance)

    with pytest.raises(AttributeError):
        i1.ra = [11.]*u.deg

def test_arraytransforms():
    """
    Test that transforms to/from ecliptic coordinates work on array coordinates
    (not testing for accuracy.)
    """
    ra = np.ones((4, ), dtype=float) * u.deg
    dec = 2*np.ones((4, ), dtype=float) * u.deg
    distance = np.ones((4, ), dtype=float) * u.au

    test_icrs = ICRS(ra=ra, dec=dec, distance=distance)
    test_gcrs = GCRS(test_icrs.data)

    bary_arr = test_icrs.transform_to(BarycentricTrueEcliptic)
    assert bary_arr.shape == ra.shape

    helio_arr = test_icrs.transform_to(HeliocentricTrueEcliptic)
    assert helio_arr.shape == ra.shape

    geo_arr = test_gcrs.transform_to(GeocentricTrueEcliptic)
    assert geo_arr.shape == ra.shape

    # now check that we also can go back the other way without shape problems
    bary_icrs = bary_arr.transform_to(ICRS)
    assert bary_icrs.shape == test_icrs.shape

    helio_icrs = helio_arr.transform_to(ICRS)
    assert helio_icrs.shape == test_icrs.shape

    geo_gcrs = geo_arr.transform_to(GCRS)
    assert geo_gcrs.shape == test_gcrs.shape

def test_realizing():
    from astropy.coordinates.builtin_frames import ICRS, FK5
    from astropy.time import Time

    rep = r.SphericalRepresentation(1*u.deg, 2*u.deg, 3*u.kpc)

    i = ICRS()
    i2 = i.realize_frame(rep)

    assert not i.has_data
    assert i2.has_data

    f = FK5(equinox=Time('J2001'))
    f2 = f.realize_frame(rep)

    assert not f.has_data
    assert f2.has_data

    assert f2.equinox == f.equinox
    assert f2.equinox != FK5.get_frame_attr_names()['equinox']

    # Check that a nicer error message is returned:
    with pytest.raises(TypeError) as excinfo:
        f.realize_frame(f.representation_type)

    assert ('Class passed as data instead of a representation' in
            excinfo.value.args[0])

def test_all_arg_options(kwargs):
    # Above is a list of all possible valid combinations of arguments.
    # Here we do a simple thing and just verify that passing them in, we have
    # access to the relevant attributes from the resulting object
    icrs = ICRS(**kwargs)
    gal = icrs.transform_to(Galactic)
    repr_gal = repr(gal)

    for k in kwargs:
        if k == 'differential_type':
            continue
        getattr(icrs, k)

    if 'pm_ra_cosdec' in kwargs: # should have both
        assert 'pm_l_cosb' in repr_gal
        assert 'pm_b' in repr_gal
        assert 'mas / yr' in repr_gal

        if 'radial_velocity' not in kwargs:
            assert 'radial_velocity' not in repr_gal

    if 'radial_velocity' in kwargs:
        assert 'radial_velocity' in repr_gal
        assert 'km / s' in repr_gal

        if 'pm_ra_cosdec' not in kwargs:
            assert 'pm_l_cosb' not in repr_gal
            assert 'pm_b' not in repr_gal

def test_transform_to_nonscalar_nodata_frame():
    # https://github.com/astropy/astropy/pull/5254#issuecomment-241592353
    from astropy.coordinates.builtin_frames import ICRS, FK5
    from astropy.time import Time
    times = Time('2016-08-23') + np.linspace(0, 10, 12)*u.day
    coo1 = ICRS(ra=[[0.], [10.], [20.]]*u.deg,
                dec=[[-30.], [30.], [60.]]*u.deg)
    coo2 = coo1.transform_to(FK5(equinox=times))
    assert coo2.shape == (3, 12)

def test_getitem_representation():
    """
    Make sure current representation survives __getitem__ even if different
    from data representation.
    """
    from astropy.coordinates.builtin_frames import ICRS
    c = ICRS([1, 1] * u.deg, [2, 2] * u.deg)
    c.representation_type = 'cartesian'
    assert c[0].representation_type is r.CartesianRepresentation

def test_skyoffset_velocity():
    c = ICRS(ra=170.9*u.deg, dec=-78.4*u.deg,
             pm_ra_cosdec=74.4134*u.mas/u.yr,
             pm_dec=-93.2342*u.mas/u.yr)
    skyoffset_frame = SkyOffsetFrame(origin=c)
    c_skyoffset = c.transform_to(skyoffset_frame)

    assert_allclose(c_skyoffset.pm_lon_coslat, c.pm_ra_cosdec)
    assert_allclose(c_skyoffset.pm_lat, c.pm_dec)

def test_rotation(rotation, expectedlatlon):
    origin = ICRS(45*u.deg, 45*u.deg)
    target = ICRS(45*u.deg, 46*u.deg)

    aframe = SkyOffsetFrame(origin=origin, rotation=rotation)
    trans = target.transform_to(aframe)

    assert_allclose([trans.lon.wrap_at(180*u.deg), trans.lat],
                    expectedlatlon, atol=1e-10*u.deg)

def test_3d_separations():
    """
    Test 3D separation functionality
    """
    c1 = ICRS(ra=1*u.deg, dec=1*u.deg, distance=9*u.kpc)
    c2 = ICRS(ra=1*u.deg, dec=1*u.deg, distance=10*u.kpc)

    sep3d = c2.separation_3d(c1)

    assert isinstance(sep3d, Distance)
    assert_allclose(sep3d - 1*u.kpc, 0*u.kpc, atol=1e-12*u.kpc)

def test_slicing_preserves_differential():
    icrs = ICRS(ra=37.4*u.deg, dec=-55.8*u.deg, distance=150*u.pc,
                pm_ra_cosdec=-21.2*u.mas/u.yr, pm_dec=17.1*u.mas/u.yr,
                radial_velocity=105.7*u.km/u.s)
    icrs2 = icrs.reshape(1,1)[:1,0]

    for name in icrs.representation_component_names.keys():
        assert getattr(icrs, name) == getattr(icrs2, name)[0]

    for name in icrs.get_representation_component_names('s').keys():
        assert getattr(icrs, name) == getattr(icrs2, name)[0]

def test_ecliptic_true_mean(trueframe, meanframe):
    """
    Check that the ecliptic true/mean transformations at least roundtrip
    """
    icrs = ICRS(1*u.deg, 2*u.deg, distance=1.5*R_sun)

    truecoo = icrs.transform_to(trueframe)
    meancoo = icrs.transform_to(meanframe)
    truecoo2 = icrs.transform_to(trueframe)

    assert not quantity_allclose(truecoo.cartesian.xyz, meancoo.cartesian.xyz)
    assert quantity_allclose(truecoo.cartesian.xyz, truecoo2.cartesian.xyz)

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])