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# -*- coding: utf-8 -*-
# Licensed under a 3-clause BSD style license - see LICENSE.rst
from __future__ import (absolute_import, division, print_function,
unicode_literals)
"""
Tests for the projected separation stuff
"""
import numpy as np
from ...tests.helper import pytest, assert_quantity_allclose as assert_allclose
from ...extern.six.moves import zip
from ... import units as u
from ..builtin_frames import ICRS, FK5, Galactic
from .. import Angle, Distance
# lon1, lat1, lon2, lat2 in degrees
coords = [(1, 0, 0, 0),
(0, 1, 0, 0),
(0, 0, 1, 0),
(0, 0, 0, 1),
(0, 0, 10, 0),
(0, 0, 90, 0),
(0, 0, 180, 0),
(0, 45, 0, -45),
(0, 60, 0, -30),
(-135, -15, 45, 15),
(100, -89, -80, 89),
(0, 0, 0, 0),
(0, 0, 1. / 60., 1. / 60.)]
correct_seps = [1, 1, 1, 1, 10, 90, 180, 90, 90, 180, 180, 0,
0.023570225877234643]
correctness_margin = 2e-10
def test_angsep():
"""
Tests that the angular separation object also behaves correctly.
"""
from ..angle_utilities import angular_separation
# check it both works with floats in radians, Quantities, or Angles
for conv in (np.deg2rad,
lambda x: u.Quantity(x, "deg"),
lambda x: Angle(x, "deg")):
for (lon1, lat1, lon2, lat2), corrsep in zip(coords, correct_seps):
angsep = angular_separation(conv(lon1), conv(lat1),
conv(lon2), conv(lat2))
assert np.fabs(angsep - conv(corrsep)) < conv(correctness_margin)
def test_fk5_seps():
"""
This tests if `separation` works for FK5 objects.
This is a regression test for github issue #891
"""
a = FK5(1.*u.deg, 1.*u.deg)
b = FK5(2.*u.deg, 2.*u.deg)
a.separation(b)
def test_proj_separations():
"""
Test angular separation functionality
"""
c1 = ICRS(ra=0*u.deg, dec=0*u.deg)
c2 = ICRS(ra=0*u.deg, dec=1*u.deg)
sep = c2.separation(c1)
#returns an Angle object
assert isinstance(sep, Angle)
assert sep.degree == 1
assert_allclose(sep.arcminute, 60.)
# these operations have ambiguous interpretations for points on a sphere
with pytest.raises(TypeError):
c1 + c2
with pytest.raises(TypeError):
c1 - c2
ngp = Galactic(l=0*u.degree, b=90*u.degree)
ncp = ICRS(ra=0*u.degree, dec=90*u.degree)
# if there is a defined conversion between the relevant coordinate systems,
# it will be automatically performed to get the right angular separation
assert_allclose(ncp.separation(ngp.transform_to(ICRS)).degree,
ncp.separation(ngp).degree)
# distance from the north galactic pole to celestial pole
assert_allclose(ncp.separation(ngp.transform_to(ICRS)).degree,
62.87174758503201)
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)
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