Python astropy.units.degree() Examples

def test_angle_string():
    with pytest.warns(IllegalSecondWarning):
        a = Angle('00:00:60', u.deg)
    assert str(a) == '0d01m00s'
    a = Angle('-00:00:10', u.hour)
    assert str(a) == '-0h00m10s'
    a = Angle(3.2, u.radian)
    assert str(a) == '3.2rad'
    a = Angle(4.2, u.microarcsecond)
    assert str(a) == '4.2uarcsec'
    a = Angle('1.0uarcsec')
    assert a.value == 1.0
    assert a.unit == u.microarcsecond
    a = Angle("3d")
    assert_allclose(a.value, 3.0)
    assert a.unit == u.degree
    a = Angle('10"')
    assert_allclose(a.value, 10.0)
    assert a.unit == u.arcsecond
    a = Angle("10'")
    assert_allclose(a.value, 10.0)
    assert a.unit == u.arcminute 

def test_obstime():
    """
    Checks to make sure observation time is
    accounted for at least in FK4 <-> ICRS transformations
    """
    b1950 = Time('B1950')
    j1975 = Time('J1975')

    fk4_50 = FK4(ra=1*u.deg, dec=2*u.deg, obstime=b1950)
    fk4_75 = FK4(ra=1*u.deg, dec=2*u.deg, obstime=j1975)

    icrs_50 = fk4_50.transform_to(ICRS)
    icrs_75 = fk4_75.transform_to(ICRS)

    # now check that the resulting coordinates are *different* - they should be,
    # because the obstime is different
    assert icrs_50.ra.degree != icrs_75.ra.degree
    assert icrs_50.dec.degree != icrs_75.dec.degree

# ------------------------------------------------------------------------------
# Affine transform tests and helpers:

# just acting as a namespace 

def test_matching_function():
    from astropy.coordinates import ICRS
    from astropy.coordinates.matching import match_coordinates_3d
    # this only uses match_coordinates_3d because that's the actual implementation

    cmatch = ICRS([4, 2.1]*u.degree, [0, 0]*u.degree)
    ccatalog = ICRS([1, 2, 3, 4]*u.degree, [0, 0, 0, 0]*u.degree)

    idx, d2d, d3d = match_coordinates_3d(cmatch, ccatalog)
    npt.assert_array_equal(idx, [3, 1])
    npt.assert_array_almost_equal(d2d.degree, [0, 0.1])
    assert d3d.value[0] == 0

    idx, d2d, d3d = match_coordinates_3d(cmatch, ccatalog, nthneighbor=2)
    assert np.all(idx == 2)
    npt.assert_array_almost_equal(d2d.degree, [1, 0.9])
    npt.assert_array_less(d3d.value, 0.02) 

def test_matching_function_3d_and_sky():
    from astropy.coordinates import ICRS
    from astropy.coordinates.matching import match_coordinates_3d, match_coordinates_sky

    cmatch = ICRS([4, 2.1]*u.degree, [0, 0]*u.degree, distance=[1, 5] * u.kpc)
    ccatalog = ICRS([1, 2, 3, 4]*u.degree, [0, 0, 0, 0]*u.degree, distance=[1, 1, 1, 5] * u.kpc)

    idx, d2d, d3d = match_coordinates_3d(cmatch, ccatalog)
    npt.assert_array_equal(idx, [2, 3])

    assert_allclose(d2d, [1, 1.9] * u.deg)
    assert np.abs(d3d[0].to_value(u.kpc) - np.radians(1)) < 1e-6
    assert np.abs(d3d[1].to_value(u.kpc) - 5*np.radians(1.9)) < 1e-5

    idx, d2d, d3d = match_coordinates_sky(cmatch, ccatalog)
    npt.assert_array_equal(idx, [3, 1])

    assert_allclose(d2d, [0, 0.1] * u.deg)
    assert_allclose(d3d, [4, 4.0000019] * u.kpc) 

def test_fk5_galactic():
    """
    Check that FK5 -> Galactic gives the same as FK5 -> FK4 -> Galactic.
    """

    fk5 = FK5(ra=1*u.deg, dec=2*u.deg)

    direct = fk5.transform_to(Galactic)
    indirect = fk5.transform_to(FK4).transform_to(Galactic)

    assert direct.separation(indirect).degree < 1.e-10

    direct = fk5.transform_to(Galactic)
    indirect = fk5.transform_to(FK4NoETerms).transform_to(Galactic)

    assert direct.separation(indirect).degree < 1.e-10 

def test_to_string_precision():
    # There are already some tests in test_api.py, but this is a regression
    # test for the bug in issue #1319 which caused incorrect formatting of the
    # seconds for precision=0

    angle = Angle(-1.23456789, unit=u.degree)

    assert angle.to_string(precision=3) == '-1d14m04.444s'
    assert angle.to_string(precision=1) == '-1d14m04.4s'
    assert angle.to_string(precision=0) == '-1d14m04s'

    angle2 = Angle(-1.23456789, unit=u.hourangle)

    assert angle2.to_string(precision=3, unit=u.hour) == '-1h14m04.444s'
    assert angle2.to_string(precision=1, unit=u.hour) == '-1h14m04.4s'
    assert angle2.to_string(precision=0, unit=u.hour) == '-1h14m04s'

    # Regression test for #7141
    angle3 = Angle(-0.5, unit=u.degree)
    assert angle3.to_string(precision=0, fields=3) == '-0d30m00s'
    assert angle3.to_string(precision=0, fields=2) == '-0d30m'
    assert angle3.to_string(precision=0, fields=1) == '-1d' 

def test_to_string_decimal():

    # There are already some tests in test_api.py, but this is a regression
    # test for the bug in issue #1323 which caused decimal formatting to not
    # work

    angle1 = Angle(2., unit=u.degree)

    assert angle1.to_string(decimal=True, precision=3) == '2.000'
    assert angle1.to_string(decimal=True, precision=1) == '2.0'
    assert angle1.to_string(decimal=True, precision=0) == '2'

    angle2 = Angle(3., unit=u.hourangle)

    assert angle2.to_string(decimal=True, precision=3) == '3.000'
    assert angle2.to_string(decimal=True, precision=1) == '3.0'
    assert angle2.to_string(decimal=True, precision=0) == '3'

    angle3 = Angle(4., unit=u.radian)

    assert angle3.to_string(decimal=True, precision=3) == '4.000'
    assert angle3.to_string(decimal=True, precision=1) == '4.0'
    assert angle3.to_string(decimal=True, precision=0) == '4' 

def __init__(self, phi, theta, r, differentials=None, copy=True):
        super().__init__(phi, theta, r, copy=copy, differentials=differentials)

        # Wrap/validate phi/theta
        if copy:
            self._phi = self._phi.wrap_at(360 * u.deg)
        else:
            # necessary because the above version of `wrap_at` has to be a copy
            self._phi.wrap_at(360 * u.deg, inplace=True)

        if np.any(self._theta < 0.*u.deg) or np.any(self._theta > 180.*u.deg):
            raise ValueError('Inclination angle(s) must be within '
                             '0 deg <= angle <= 180 deg, '
                             'got {}'.format(theta.to(u.degree)))

        if self._r.unit.physical_type == 'length':
            self._r = self._r.view(Distance) 

def get_total_spatial_integral(self, z=None):  
        """
        Returns the total integral (for 2D functions) or the integral over the spatial components (for 3D functions).
        needs to be implemented in subclasses.

        :return: an array of values of the integral (same dimension as z).
        """

        dL= self.l_max.value-self.l_min.value if self.l_max.value > self.l_min.value else 360 + self.l_max.value - self.l_max.value

        #integral -inf to inf exp(-b**2 / 2*sigma_b**2 ) db = sqrt(2pi)*sigma_b 
        #Note that K refers to the peak diffuse flux (at b = 0) per square degree.
        integral = np.sqrt( 2*np.pi ) * self.sigma_b.value * self.K.value * dL 

        if isinstance( z, u.Quantity):
            z = z.value
        return integral * np.power( 180. / np.pi, -2 ) * np.ones_like( z ) 

def test_position_angle():
    c1 = SkyCoord(0*u.deg, 0*u.deg)

    c2 = SkyCoord(1*u.deg, 0*u.deg)
    assert_allclose(c1.position_angle(c2) - 90.0 * u.deg, 0*u.deg)

    c3 = SkyCoord(1*u.deg, 0.1*u.deg)
    assert c1.position_angle(c3) < 90*u.deg

    c4 = SkyCoord(0*u.deg, 1*u.deg)
    assert_allclose(c1.position_angle(c4), 0*u.deg)

    carr1 = SkyCoord(0*u.deg, [0, 1, 2]*u.deg)
    carr2 = SkyCoord([-1, -2, -3]*u.deg, [0.1, 1.1, 2.1]*u.deg)

    res = carr1.position_angle(carr2)
    assert res.shape == (3,)
    assert np.all(res < 360*u.degree)
    assert np.all(res > 270*u.degree)

    cicrs = SkyCoord(0*u.deg, 0*u.deg, frame='icrs')
    cfk5 = SkyCoord(1*u.deg, 0*u.deg, frame='fk5')
    # because of the frame transform, it's just a *bit* more than 90 degrees
    assert cicrs.position_angle(cfk5) > 90.0 * u.deg
    assert cicrs.position_angle(cfk5) < 91.0 * u.deg 

def test_sep_pa_equivalence():
    """Regression check for bug in #5702.

    PA and separation from object 1 to 2 should be consistent with those
    from 2 to 1
    """
    cfk5 = SkyCoord(1*u.deg, 0*u.deg, frame='fk5')
    cfk5B1950 = SkyCoord(1*u.deg, 0*u.deg, frame='fk5', equinox='B1950')
    # test with both default and explicit equinox #5722 and #3106
    sep_forward = cfk5.separation(cfk5B1950)
    sep_backward = cfk5B1950.separation(cfk5)
    assert sep_forward != 0 and sep_backward != 0
    assert_allclose(sep_forward, sep_backward)
    posang_forward = cfk5.position_angle(cfk5B1950)
    posang_backward = cfk5B1950.position_angle(cfk5)
    assert posang_forward != 0 and posang_backward != 0
    assert 179 < (posang_forward - posang_backward).wrap_at(360*u.deg).degree < 181
    dcfk5 = SkyCoord(1*u.deg, 0*u.deg, frame='fk5', distance=1*u.pc)
    dcfk5B1950 = SkyCoord(1*u.deg, 0*u.deg, frame='fk5', equinox='B1950',
                          distance=1.*u.pc)
    sep3d_forward = dcfk5.separation_3d(dcfk5B1950)
    sep3d_backward = dcfk5B1950.separation_3d(dcfk5)
    assert sep3d_forward != 0 and sep3d_backward != 0
    assert_allclose(sep3d_forward, sep3d_backward) 

def parse_ra_dec(header):
    try:
        coord = SkyCoord(header.get('CRVAl1'), header.get('CRVAL2'), unit=(units.degree, units.degree))
        ra = coord.ra.deg
        dec = coord.dec.deg
    except (ValueError, TypeError):
        # Fallback to RA and DEC
        try:
            coord = SkyCoord(header.get('RA'), header.get('DEC'), unit=(units.hourangle, units.degree))
            ra = coord.ra.deg
            dec = coord.dec.deg
        except (ValueError, TypeError):
            # Fallback to Cat-RA and CAT-DEC
            try:
                coord = SkyCoord(header.get('CAT-RA'), header.get('CAT-DEC'), unit=(units.hourangle, units.degree))
                ra = coord.ra.deg
                dec = coord.dec.deg
            except (ValueError, TypeError) as e:
                logger.error('Could not get initial pointing guess. {0}'.format(e),
                             extra_tags={'filename': header.get('ORIGNAME')})
                ra, dec = np.nan, np.nan
    return ra, dec 

def test_search_around():
    """
    Test the search_around_* methods

    Here we don't actually test the values are right, just that the methods of
    SkyCoord work.  The accuracy tests are in ``test_matching.py``
    """
    from astropy.utils import NumpyRNGContext

    with NumpyRNGContext(987654321):
        sc1 = SkyCoord(np.random.rand(20) * 360.*u.degree,
                      (np.random.rand(20) * 180. - 90.)*u.degree)
        sc2 = SkyCoord(np.random.rand(100) * 360. * u.degree,
                      (np.random.rand(100) * 180. - 90.)*u.degree)

        sc1ds = SkyCoord(ra=sc1.ra, dec=sc1.dec, distance=np.random.rand(20)*u.kpc)
        sc2ds = SkyCoord(ra=sc2.ra, dec=sc2.dec, distance=np.random.rand(100)*u.kpc)

    idx1_sky, idx2_sky, d2d_sky, d3d_sky = sc1.search_around_sky(sc2, 10*u.deg)
    idx1_3d, idx2_3d, d2d_3d, d3d_3d = sc1ds.search_around_3d(sc2ds, 250*u.pc) 

def circle2circle(line):
    """
    Parse a string that describes a circle in ds9 format.

    Parameters
    ----------
    line : str
        A string containing a DS9 region command for a circle.

    Returns
    -------
    circle : [ra, dec, radius]
        The center and radius of the circle.
    """
    words = re.split('[(,\s)]', line)
    ra = words[1]
    dec = words[2]
    radius = words[3][:-1]  # strip the "
    if ":" in ra:
        ra = Angle(ra, unit=u.hour)
    else:
        ra = Angle(ra, unit=u.degree)
    dec = Angle(dec, unit=u.degree)
    radius = Angle(radius, unit=u.arcsecond)
    return [ra.degree, dec.degree, radius.degree] 

def test_init_with_frame_instance_keyword():

    # Frame instance
    c1 = SkyCoord(3 * u.deg, 4 * u.deg,
                  frame=FK5(equinox='J2010'))
    assert c1.equinox == Time('J2010')

    # Frame instance with data (data gets ignored)
    c2 = SkyCoord(3 * u.deg, 4 * u.deg,
                 frame=FK5(1. * u.deg, 2 * u.deg,
                 equinox='J2010'))
    assert c2.equinox == Time('J2010')
    assert allclose(c2.ra.degree, 3)
    assert allclose(c2.dec.degree, 4)

    # SkyCoord instance
    c3 = SkyCoord(3 * u.deg, 4 * u.deg, frame=c1)
    assert c3.equinox == Time('J2010')

    # Check duplicate arguments
    with pytest.raises(ValueError) as err:
        c = SkyCoord(3 * u.deg, 4 * u.deg, frame=FK5(equinox='J2010'), equinox='J2001')
    assert "Cannot specify frame attribute 'equinox'" in str(err.value) 

def test_angle_methods():
    # Most methods tested as part of the Quantity tests.
    # A few tests here which caused problems before: #8368
    a = Angle([0., 2.], 'deg')
    a_mean = a.mean()
    assert type(a_mean) is Angle
    assert a_mean == 1. * u.degree
    a_std = a.std()
    assert type(a_std) is Angle
    assert a_std == 1. * u.degree
    a_var = a.var()
    assert type(a_var) is u.Quantity
    assert a_var == 1. * u.degree ** 2
    a_ptp = a.ptp()
    assert type(a_ptp) is Angle
    assert a_ptp == 2. * u.degree
    a_max = a.max()
    assert type(a_max) is Angle
    assert a_max == 2. * u.degree
    a_min = a.min()
    assert type(a_min) is Angle
    assert a_min == 0. * u.degree 

def test_angle_format_roundtripping():
    """
    Ensures that the string representation of an angle can be used to create a
    new valid Angle.
    """

    a1 = Angle(0, unit=u.radian)
    a2 = Angle(10, unit=u.degree)
    a3 = Angle(0.543, unit=u.degree)
    a4 = Angle('1d2m3.4s')

    assert Angle(str(a1)).degree == a1.degree
    assert Angle(str(a2)).degree == a2.degree
    assert Angle(str(a3)).degree == a3.degree
    assert Angle(str(a4)).degree == a4.degree

    # also check Longitude/Latitude
    ra = Longitude('1h2m3.4s')
    dec = Latitude('1d2m3.4s')

    assert_allclose(Angle(str(ra)).degree, ra.degree)
    assert_allclose(Angle(str(dec)).degree, dec.degree) 

def write_reg(self, filename):
        """
        Write a ds9 region file that represents this region as a set of diamonds.

        Parameters
        ----------
        filename : str
            File to write
        """
        with open(filename, 'w') as out:
            for d in range(1, self.maxdepth+1):
                for p in self.pixeldict[d]:
                    line = "fk5; polygon("
                    # the following int() gets around some problems with np.int64 that exist prior to numpy v 1.8.1
                    vectors = list(zip(*hp.boundaries(2**d, int(p), step=1, nest=True)))
                    positions = []
                    for sky in self.vec2sky(np.array(vectors), degrees=True):
                        ra, dec = sky
                        pos = SkyCoord(ra/15, dec, unit=(u.degree, u.degree))
                        positions.append(pos.ra.to_string(sep=':', precision=2))
                        positions.append(pos.dec.to_string(sep=':', precision=2))
                    line += ','.join(positions)
                    line += ")"
                    print(line, file=out)
        return 

def test_init_lonlat(self):

        s2 = SphericalRepresentation(Longitude(8, u.hour),
                                     Latitude(5, u.deg),
                                     Distance(10, u.kpc))

        assert s2.lon == 8. * u.hourangle
        assert s2.lat == 5. * u.deg
        assert s2.distance == 10. * u.kpc

        assert isinstance(s2.lon, Longitude)
        assert isinstance(s2.lat, Latitude)
        assert isinstance(s2.distance, Distance)

        # also test that wrap_angle is preserved
        s3 = SphericalRepresentation(Longitude(-90, u.degree,
                                               wrap_angle=180*u.degree),
                                     Latitude(-45, u.degree),
                                     Distance(1., u.Rsun))
        assert s3.lon == -90. * u.degree
        assert s3.lon.wrap_angle == 180 * u.degree 

def test_init_float32_array(self):
        """Regression test against #2983"""
        lon = Longitude(np.float32([1., 2.]), u.degree)
        lat = Latitude(np.float32([3., 4.]), u.degree)
        s1 = UnitSphericalRepresentation(lon=lon, lat=lat, copy=False)
        assert s1.lon.dtype == np.float32
        assert s1.lat.dtype == np.float32
        assert s1._values['lon'].dtype == np.float32
        assert s1._values['lat'].dtype == np.float32 

def test_negative_fifty_nine_sixty_dms():
    # Test for DMS parser
    with pytest.warns(IllegalSecondWarning):
        a = Angle('-00:59:60', u.deg)
    assert_allclose(a.degree, -1.) 

def test_transform_classes():
    """
    Tests the class-based/OO syntax for creating transforms
    """

    tfun = lambda c, f: f.__class__(ra=c.ra, dec=c.dec)
    trans1 = t.FunctionTransform(tfun, TCoo1, TCoo2,
                        register_graph=frame_transform_graph)

    c1 = TCoo1(ra=1*u.radian, dec=0.5*u.radian)
    c2 = c1.transform_to(TCoo2)
    assert_allclose(c2.ra.radian, 1)
    assert_allclose(c2.dec.radian, 0.5)

    def matfunc(coo, fr):
        return [[1, 0, 0],
                [0, coo.ra.degree, 0],
                [0, 0, 1]]
    trans2 = t.DynamicMatrixTransform(matfunc, TCoo1, TCoo2)
    trans2.register(frame_transform_graph)

    c3 = TCoo1(ra=1*u.deg, dec=2*u.deg)
    c4 = c3.transform_to(TCoo2)

    assert_allclose(c4.ra.degree, 1)
    assert_allclose(c4.ra.degree, 1)

    # be sure to unregister the second one - no need for trans1 because it
    # already got unregistered when trans2 was created.
    trans2.unregister(frame_transform_graph) 

def hours_to_hms(h):
    """
    Convert an floating-point hour value into an ``(hour, minute,
    second)`` tuple.
    """

    sign = np.copysign(1.0, h)

    (hf, h) = np.modf(np.abs(h))  # (degree fraction, degree)
    (mf, m) = np.modf(hf * 60.0)  # (minute fraction, minute)
    s = mf * 60.0

    return (np.floor(sign * h), sign * np.floor(m), sign * s) 

def hms_to_radians(h, m, s):
    """
    Convert hour, minute, second to a float radians value.
    """

    return u.degree.to(u.radian, hms_to_degrees(h, m, s)) 

def radians_to_degrees(r):
    """
    Convert an angle in Radians to Degrees.
    """
    return u.radian.to(u.degree, r) 

def test_broadcasting(self):

        s1 = PhysicsSphericalRepresentation(phi=[8, 9] * u.hourangle,
                                            theta=[5, 6] * u.deg,
                                            r=10 * u.kpc)

        assert_allclose_quantity(s1.phi, [120, 135] * u.degree)
        assert_allclose_quantity(s1.theta, [5, 6] * u.degree)
        assert_allclose_quantity(s1.r, [10, 10] * u.kpc) 

def test_init_array(self):

        s1 = SphericalRepresentation(lon=[8, 9] * u.hourangle,
                                     lat=[5, 6] * u.deg,
                                     distance=[1, 2] * u.kpc)

        assert_allclose(s1.lon.degree, [120, 135])
        assert_allclose(s1.lat.degree, [5, 6])
        assert_allclose(s1.distance.kpc, [1, 2])

        assert isinstance(s1.lon, Longitude)
        assert isinstance(s1.lat, Latitude)
        assert isinstance(s1.distance, Distance) 

def test_init_array(self):

        s1 = PhysicsSphericalRepresentation(phi=[8, 9] * u.hourangle,
                                            theta=[5, 6] * u.deg,
                                            r=[1, 2] * u.kpc)

        assert_allclose(s1.phi.degree, [120, 135])
        assert_allclose(s1.theta.degree, [5, 6])
        assert_allclose(s1.r.kpc, [1, 2])

        assert isinstance(s1.phi, Angle)
        assert isinstance(s1.theta, Angle)
        assert isinstance(s1.r, Distance) 

def test_broadcasting(self):

        s1 = UnitSphericalRepresentation(lon=[8, 9] * u.hourangle,
                                         lat=[5, 6] * u.deg)

        assert_allclose_quantity(s1.lon, [120, 135] * u.degree)
        assert_allclose_quantity(s1.lat, [5, 6] * u.degree) 

def test_init_array(self):

        s1 = UnitSphericalRepresentation(lon=[8, 9] * u.hourangle,
                                         lat=[5, 6] * u.deg)

        assert_allclose(s1.lon.degree, [120, 135])
        assert_allclose(s1.lat.degree, [5, 6])

        assert isinstance(s1.lon, Longitude)
        assert isinstance(s1.lat, Latitude)