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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)
import numpy as np
from ... import units as u
from ..distances import Distance
from ..builtin_frames import ICRS, FK5, Galactic, AltAz, SkyOffsetFrame
from .. import SkyCoord, EarthLocation
from ...time import Time
from ...tests.helper import (pytest, quantity_allclose as allclose,
assert_quantity_allclose as assert_allclose)
from ...extern.six.moves import range
@pytest.mark.parametrize("inradec,expectedlatlon, tolsep", [
((45, 45)*u.deg, (0, 0)*u.deg, .001*u.arcsec),
((45, 0)*u.deg, (0, -45)*u.deg, .001*u.arcsec),
((45, 90)*u.deg, (0, 45)*u.deg, .001*u.arcsec),
((46, 45)*u.deg, (1*np.cos(45*u.deg), 0)*u.deg, 16*u.arcsec),
])
def test_skyoffset(inradec, expectedlatlon, tolsep, originradec=(45, 45)*u.deg):
origin = ICRS(*originradec)
skyoffset_frame = SkyOffsetFrame(origin=origin)
skycoord = SkyCoord(*inradec, frame=ICRS)
skycoord_inaf = skycoord.transform_to(skyoffset_frame)
assert hasattr(skycoord_inaf, 'lon')
assert hasattr(skycoord_inaf, 'lat')
expected = SkyCoord(*expectedlatlon, frame=skyoffset_frame)
assert skycoord_inaf.separation(expected) < tolsep
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_skyoffset_functional_dec():
# 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]
input_ra_rad = np.deg2rad(input_ra)
input_dec_rad = np.deg2rad(input_dec)
icrs_coord = ICRS(ra=input_ra*u.deg,
dec=input_dec*u.deg,
distance=1.*u.kpc)
#Dec rotations
#Done in xyz space because dec must be [-90,90]
for dec in np.linspace(-90, 90, 13):
# expected rotation
dec_rad = -np.deg2rad(dec)
expected_x = (-np.sin(input_dec_rad) * np.sin(dec_rad) +
np.cos(input_ra_rad) * np.cos(input_dec_rad) * np.cos(dec_rad))
expected_y = (np.sin(input_ra_rad) * np.cos(input_dec_rad))
expected_z = (np.sin(input_dec_rad) * np.cos(dec_rad) +
np.sin(dec_rad) * np.cos(input_ra_rad) * np.cos(input_dec_rad))
expected = SkyCoord(x=expected_x,
y=expected_y,
z=expected_z, unit='kpc', representation='cartesian')
expected_xyz = expected.cartesian.xyz
# actual transformation to the frame
skyoffset_frame = SkyOffsetFrame(origin=ICRS(0*u.deg, dec*u.deg))
actual = icrs_coord.transform_to(skyoffset_frame)
actual_xyz = actual.cartesian.xyz
# back to ICRS
roundtrip = actual.transform_to(ICRS)
# 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_skyoffset_functional_ra_dec():
# 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]
input_ra_rad = np.deg2rad(input_ra)
input_dec_rad = np.deg2rad(input_dec)
icrs_coord = ICRS(ra = input_ra*u.deg,
dec = input_dec*u.deg,
distance=1.*u.kpc)
for ra in np.linspace(0, 360, 10):
for dec in np.linspace(-90, 90, 5):
# expected rotation
dec_rad = -np.deg2rad(dec)
ra_rad = np.deg2rad(ra)
expected_x = (-np.sin(input_dec_rad) * np.sin(dec_rad) +
np.cos(input_ra_rad) * np.cos(input_dec_rad) * np.cos(dec_rad) * np.cos(ra_rad) +
np.sin(input_ra_rad) * np.cos(input_dec_rad) * np.cos(dec_rad) * np.sin(ra_rad))
expected_y = (np.sin(input_ra_rad) * np.cos(input_dec_rad) * np.cos(ra_rad) -
np.cos(input_ra_rad) * np.cos(input_dec_rad) * np.sin(ra_rad))
expected_z = (np.sin(input_dec_rad) * np.cos(dec_rad) +
np.sin(dec_rad) * np.cos(ra_rad) * np.cos(input_ra_rad) * np.cos(input_dec_rad) +
np.sin(dec_rad) * np.sin(ra_rad) * np.sin(input_ra_rad) * np.cos(input_dec_rad))
expected = SkyCoord(x=expected_x,
y=expected_y,
z=expected_z, unit='kpc', representation='cartesian')
expected_xyz = expected.cartesian.xyz
# actual transformation to the frame
skyoffset_frame = SkyOffsetFrame(origin=ICRS(ra*u.deg, dec*u.deg))
actual = icrs_coord.transform_to(skyoffset_frame)
actual_xyz = actual.cartesian.xyz
# back to ICRS
roundtrip = actual.transform_to(ICRS)
# Verify
assert_allclose(actual_xyz, expected_xyz, atol=1E-5*u.kpc)
assert_allclose(icrs_coord.ra, roundtrip.ra, atol=1E-4*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_skycoord_skyoffset_frame():
m31 = SkyCoord(10.6847083, 41.26875, frame='icrs', unit=u.deg)
m33 = SkyCoord(23.4621, 30.6599417, frame='icrs', unit=u.deg)
m31_astro = m31.skyoffset_frame()
m31_in_m31 = m31.transform_to(m31_astro)
m33_in_m31 = m33.transform_to(m31_astro)
assert_allclose([m31_in_m31.lon, m31_in_m31.lat], [0, 0]*u.deg, atol=1e-10*u.deg)
assert_allclose([m33_in_m31.lon, m33_in_m31.lat], [11.13135175, -9.79084759]*u.deg)
assert_allclose(m33.separation(m31),
np.hypot(m33_in_m31.lon, m33_in_m31.lat),
atol=.1*u.deg)
# used below in the next parametrized test
m31_sys = [ICRS, FK5, Galactic]
m31_coo = [(10.6847929, 41.2690650), (10.6847929, 41.2690650), (121.1744050, -21.5729360)]
m31_dist = Distance(770, u.kpc)
convert_precision = 1 * u.arcsec
roundtrip_precision = 1e-4 * u.degree
dist_precision = 1e-9 * u.kpc
m31_params = []
for i in range(len(m31_sys)):
for j in range(len(m31_sys)):
if i < j:
m31_params.append((m31_sys[i], m31_sys[j], m31_coo[i], m31_coo[j]))
@pytest.mark.parametrize(('fromsys', 'tosys', 'fromcoo', 'tocoo'), m31_params)
def test_m31_coord_transforms(fromsys, tosys, fromcoo, tocoo):
"""
This tests a variety of coordinate conversions for the Chandra point-source
catalog location of M31 from NED, via SkyOffsetFrames
"""
from_origin = fromsys(fromcoo[0]*u.deg, fromcoo[1]*u.deg,
distance=m31_dist)
from_pos = SkyOffsetFrame(1*u.deg, 1*u.deg, origin=from_origin)
to_origin = tosys(tocoo[0]*u.deg, tocoo[1]*u.deg, distance=m31_dist)
to_astroframe = SkyOffsetFrame(origin=to_origin)
target_pos = from_pos.transform_to(to_astroframe)
assert_allclose(to_origin.separation(target_pos),
np.hypot(from_pos.lon, from_pos.lat),
atol=convert_precision)
roundtrip_pos = target_pos.transform_to(from_pos)
assert_allclose([roundtrip_pos.lon.wrap_at(180*u.deg), roundtrip_pos.lat],
[1.0*u.deg, 1.0*u.deg], atol=convert_precision)
def test_altaz_attribute_transforms():
"""Test transforms between AltAz frames with different attributes."""
el1 = EarthLocation(0*u.deg, 0*u.deg, 0*u.m)
origin1 = AltAz(0 * u.deg, 0*u.deg, obstime=Time("2000-01-01T12:00:00"),
location=el1)
frame1 = SkyOffsetFrame(origin=origin1)
coo1 = SkyCoord(1 * u.deg, 1 * u.deg, frame=frame1)
el2 = EarthLocation(0*u.deg, 0*u.deg, 0*u.m)
origin2 = AltAz(0 * u.deg, 0*u.deg, obstime=Time("2000-01-01T11:00:00"),
location=el2)
frame2 = SkyOffsetFrame(origin=origin2)
coo2 = coo1.transform_to(frame2)
coo2_expected = [1.22522446, 0.70624298] * u.deg
assert_allclose([coo2.lon.wrap_at(180*u.deg), coo2.lat],
coo2_expected, atol=convert_precision)
el3 = EarthLocation(0*u.deg, 90*u.deg, 0*u.m)
origin3 = AltAz(0 * u.deg, 90*u.deg, obstime=Time("2000-01-01T12:00:00"),
location=el3)
frame3 = SkyOffsetFrame(origin=origin3)
coo3 = coo2.transform_to(frame3)
assert_allclose([coo3.lon.wrap_at(180*u.deg), coo3.lat],
[1*u.deg, 1*u.deg], atol=convert_precision)
@pytest.mark.parametrize("rotation, expectedlatlon", [
(0*u.deg, [0, 1]*u.deg),
(180*u.deg, [0, -1]*u.deg),
(90*u.deg, [-1, 0]*u.deg),
(-90*u.deg, [1, 0]*u.deg)
])
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)
@pytest.mark.parametrize("rotation, expectedlatlon", [
(0*u.deg, [0, 1]*u.deg),
(180*u.deg, [0, -1]*u.deg),
(90*u.deg, [-1, 0]*u.deg),
(-90*u.deg, [1, 0]*u.deg)
])
def test_skycoord_skyoffset_frame_rotation(rotation, expectedlatlon):
"""Test if passing a rotation argument via SkyCoord works"""
origin = SkyCoord(45*u.deg, 45*u.deg)
target = SkyCoord(45*u.deg, 46*u.deg)
aframe = origin.skyoffset_frame(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_skyoffset_names():
origin1 = ICRS(45*u.deg, 45*u.deg)
aframe1 = SkyOffsetFrame(origin=origin1)
assert type(aframe1).__name__ == 'SkyOffsetICRS'
origin2 = Galactic(45*u.deg, 45*u.deg)
aframe2 = SkyOffsetFrame(origin=origin2)
assert type(aframe2).__name__ == 'SkyOffsetGalactic'
def test_skyoffset_origindata():
origin = ICRS()
with pytest.raises(ValueError):
SkyOffsetFrame(origin=origin)
def test_skyoffset_lonwrap():
origin = ICRS(45*u.deg, 45*u.deg)
sc = SkyCoord(190*u.deg, -45*u.deg, frame=SkyOffsetFrame(origin=origin))
assert sc.lon.to(u.deg).value < 180
|
