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# Copyright Crown and Cartopy Contributors
#
# This file is part of Cartopy and is released under the BSD 3-clause license.
# See LICENSE in the root of the repository for full licensing details.
"""
Tests for the Hammer coordinate system.
"""
import numpy as np
from numpy.testing import assert_almost_equal
import pytest
import cartopy.crs as ccrs
from .helpers import check_proj_params
def test_default():
hammer = ccrs.Hammer()
other_args = {'a=6378137.0', 'lon_0=0'}
check_proj_params('hammer', hammer, other_args)
assert_almost_equal(hammer.x_limits, [-18040095.6961473, 18040095.6961473])
assert_almost_equal(hammer.y_limits, [-9020047.8480736, 9020047.8480736])
def test_sphere_globe():
globe = ccrs.Globe(semimajor_axis=1000, ellipse=None)
hammer = ccrs.Hammer(globe=globe)
other_args = {'a=1000', 'lon_0=0'}
check_proj_params('hammer', hammer, other_args)
assert_almost_equal(hammer.x_limits, [-2828.4271247, 2828.4271247])
assert_almost_equal(hammer.y_limits, [-1414.2135624, 1414.2135624])
def test_ellipse_globe():
globe = ccrs.Globe(ellipse='WGS84')
with pytest.warns(UserWarning,
match='does not handle elliptical globes.') as w:
hammer = ccrs.Hammer(globe=globe)
assert len(w) == 1
other_args = {'ellps=WGS84', 'lon_0=0'}
check_proj_params('hammer', hammer, other_args)
# Limits are the same as default since ellipses are not supported.
assert_almost_equal(hammer.x_limits, [-18040095.6961473, 18040095.6961473])
assert_almost_equal(hammer.y_limits, [-9020047.8480736, 9020047.8480736])
def test_eccentric_globe():
globe = ccrs.Globe(semimajor_axis=1000, semiminor_axis=500,
ellipse=None)
with pytest.warns(UserWarning,
match='does not handle elliptical globes.') as w:
hammer = ccrs.Hammer(globe=globe)
assert len(w) == 1
other_args = {'a=1000', 'b=500', 'lon_0=0'}
check_proj_params('hammer', hammer, other_args)
# Limits are the same as spheres since ellipses are not supported.
assert_almost_equal(hammer.x_limits, [-2828.4271247, 2828.4271247])
assert_almost_equal(hammer.y_limits, [-1414.2135624, 1414.2135624])
def test_offset():
crs = ccrs.Hammer()
crs_offset = ccrs.Hammer(false_easting=1234, false_northing=-4321)
other_args = {'a=6378137.0', 'lon_0=0', 'x_0=1234', 'y_0=-4321'}
check_proj_params('hammer', 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
@pytest.mark.parametrize('lon', [-10.0, 10.0])
def test_central_longitude(lon):
hammer = ccrs.Hammer(central_longitude=lon)
other_args = {'a=6378137.0', 'lon_0={}'.format(lon)}
check_proj_params('hammer', hammer, other_args)
assert_almost_equal(hammer.x_limits, [-18040095.6961473, 18040095.6961473],
decimal=5)
assert_almost_equal(hammer.y_limits, [-9020047.8480736, 9020047.8480736])
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