1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
# (C) British Crown Copyright 2018, Met Office
#
# This file is part of cartopy.
#
# cartopy is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the
# Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# cartopy is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with cartopy. If not, see <https://www.gnu.org/licenses/>.
"""
Tests for the Equal Earth coordinate system.
"""
from __future__ import (absolute_import, division, print_function)
import numpy as np
from numpy.testing import assert_almost_equal
import pytest
import cartopy.crs as ccrs
pytestmark = pytest.mark.skipif(ccrs.PROJ4_VERSION < (5, 2, 0),
reason='Proj is too old.')
def check_proj_params(crs, other_args):
expected = other_args | {'proj=eqearth', 'no_defs'}
proj_params = set(crs.proj4_init.lstrip('+').split(' +'))
assert expected == proj_params
def test_default():
eqearth = ccrs.EqualEarth()
other_args = {'ellps=WGS84', 'lon_0=0'}
check_proj_params(eqearth, other_args)
assert_almost_equal(eqearth.x_limits,
[-17243959.0622169, 17243959.0622169])
assert_almost_equal(eqearth.y_limits,
[-8392927.59846646, 8392927.59846646])
# Expected aspect ratio from the paper.
assert_almost_equal(np.diff(eqearth.x_limits) / np.diff(eqearth.y_limits),
2.05458, decimal=5)
def test_offset():
crs = ccrs.EqualEarth()
crs_offset = ccrs.EqualEarth(false_easting=1234, false_northing=-4321)
other_args = {'ellps=WGS84', 'lon_0=0', 'x_0=1234', 'y_0=-4321'}
check_proj_params(crs_offset, other_args)
assert tuple(np.array(crs.x_limits) + 1234) == crs_offset.x_limits
assert tuple(np.array(crs.y_limits) - 4321) == crs_offset.y_limits
def test_eccentric_globe():
globe = ccrs.Globe(semimajor_axis=1000, semiminor_axis=500,
ellipse=None)
eqearth = ccrs.EqualEarth(globe=globe)
other_args = {'a=1000', 'b=500', 'lon_0=0'}
check_proj_params(eqearth, other_args)
assert_almost_equal(eqearth.x_limits,
[-2248.43664092550, 2248.43664092550])
assert_almost_equal(eqearth.y_limits,
[-1094.35228122148, 1094.35228122148])
# Expected aspect ratio from the paper.
assert_almost_equal(np.diff(eqearth.x_limits) / np.diff(eqearth.y_limits),
2.05458, decimal=5)
@pytest.mark.parametrize('lon', [-10.0, 10.0])
def test_central_longitude(lon):
eqearth = ccrs.EqualEarth(central_longitude=lon)
other_args = {'ellps=WGS84', 'lon_0={}'.format(lon)}
check_proj_params(eqearth, other_args)
assert_almost_equal(eqearth.x_limits,
[-17243959.0622169, 17243959.0622169], decimal=5)
assert_almost_equal(eqearth.y_limits,
[-8392927.59846646, 8392927.59846646])
# Expected aspect ratio from the paper.
assert_almost_equal(np.diff(eqearth.x_limits) / np.diff(eqearth.y_limits),
2.05458, decimal=5)
|
