code: # (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 UTM 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
  
  
  def check_proj4_params(crs, other_args):
      expected = other_args | {'proj=utm', 'no_defs', 'units=m'}
      pro4_params = set(crs.proj4_init.lstrip('+').split(' +'))
      assert expected == pro4_params
  
  
  @pytest.mark.parametrize('south', [False, True])
  def test_default(south):
      zone = 1  # Limits are fixed, so don't bother checking other zones.
      utm = ccrs.UTM(zone, southern_hemisphere=south)
      other_args = {'ellps=WGS84', 'zone={}'.format(zone)}
      if south:
          other_args |= {'south'}
      check_proj4_params(utm, other_args)
  
      assert_almost_equal(np.array(utm.x_limits),
                          [-250000, 1250000])
      assert_almost_equal(np.array(utm.y_limits),
                          [-10000000,  25000000])
  
  
  def test_ellipsoid_transform():
      # USGS Professional Paper 1395, pp 269 - 271
      globe = ccrs.Globe(ellipse='clrk66')
      utm = ccrs.UTM(zone=18, globe=globe)
      geodetic = utm.as_geodetic()
  
      other_args = {'ellps=clrk66', 'zone=18'}
      check_proj4_params(utm, other_args)
  
      assert_almost_equal(np.array(utm.x_limits),
                          [-250000, 1250000])
      assert_almost_equal(np.array(utm.y_limits),
                          [-10000000,  25000000])
  
      result = utm.transform_point(-73.5, 40.5, geodetic)
      assert_almost_equal(result, np.array([127106.5 + 500000, 4484124.4]),
                          decimal=1)
  
      inverse_result = geodetic.transform_point(result[0], result[1], utm)
      assert_almost_equal(inverse_result, [-73.5, 40.5])
  
apis: numpy.testing.assert_almost_equal numpy.array