Backport PRs for 0.20.1

lib/cartopy/mpl/geoaxes.py

@@ -1793,7 +1793,7 @@ def pcolormesh(self, *args, **kwargs):
         """
         # Add in an argument checker to handle Matplotlib's potential
         # interpolation when coordinate wraps are involved
-        args = self._wrap_args(*args, **kwargs)
+        args, kwargs = self._wrap_args(*args, **kwargs)
         result = matplotlib.axes.Axes.pcolormesh(self, *args, **kwargs)
         # Wrap the quadrilaterals if necessary
         result = self._wrap_quadmesh(result, **kwargs)
@@ -1815,8 +1815,11 @@ def _wrap_args(self, *args, **kwargs):
         if not (kwargs.get('shading', default_shading) in
                 ('nearest', 'auto') and len(args) == 3 and
                 getattr(kwargs.get('transform'), '_wrappable', False)):
-            return args
+            return args, kwargs
 
+        # We have changed the shading from nearest/auto to flat
+        # due to the addition of an extra coordinate
+        kwargs['shading'] = 'flat'
         X = np.asanyarray(args[0])
         Y = np.asanyarray(args[1])
         nrows, ncols = np.asanyarray(args[2]).shape
@@ -1852,7 +1855,7 @@ def _interp_grid(X, wrap=0):
             X = _interp_grid(X.T, wrap=xwrap).T
             Y = _interp_grid(Y.T).T
 
-        return (X, Y, args[2])
+        return (X, Y, args[2]), kwargs
 
     def _wrap_quadmesh(self, collection, **kwargs):
         """
@@ -1868,8 +1871,13 @@ def _wrap_quadmesh(self, collection, **kwargs):
         # Get the quadmesh data coordinates
         coords = collection._coordinates
         Ny, Nx, _ = coords.shape
+        if kwargs.get('shading') == 'gouraud':
+            # Gouraud shading has the same shape for coords and data
+            data_shape = Ny, Nx
+        else:
+            data_shape = Ny - 1, Nx - 1
         # data array
-        C = collection.get_array().reshape((Ny - 1, Nx - 1))
+        C = collection.get_array().reshape(data_shape)
 
         transformed_pts = self.projection.transform_points(
             t, coords[..., 0], coords[..., 1])
@@ -1898,6 +1906,23 @@ def _wrap_quadmesh(self, collection, **kwargs):
             # No wrapping needed
             return collection
 
+        # Wrapping with gouraud shading is error-prone. We will do our best,
+        # but pcolor does not handle gouraud shading, so there needs to be
+        # another way to handle the wrapped cells.
+        if kwargs.get('shading') == 'gouraud':
+            warnings.warn("Handling wrapped coordinates with gouraud "
+                          "shading is likely to introduce artifacts. "
+                          "It is recommended to remove the wrap manually "
+                          "before calling pcolormesh.")
+            # With gouraud shading, we actually want an (Ny, Nx) shaped mask
+            gmask = np.zeros(data_shape, dtype=bool)
+            # If any of the cells were wrapped, apply it to all 4 corners
+            gmask[:-1, :-1] |= mask
+            gmask[1:, :-1] |= mask
+            gmask[1:, 1:] |= mask
+            gmask[:-1, 1:] |= mask
+            mask = gmask
+
         # We have quadrilaterals that cross the wrap boundary
         # Now, we need to update the original collection with
         # a mask over those cells and use pcolor to draw those
@@ -1978,7 +2003,11 @@ def pcolor(self, *args, **kwargs):
         """
         # Add in an argument checker to handle Matplotlib's potential
         # interpolation when coordinate wraps are involved
-        args = self._wrap_args(*args, **kwargs)
+        args, kwargs = self._wrap_args(*args, **kwargs)
+        if matplotlib.__version__ < "3.3":
+            # MPL 3.3 introduced the shading option, and it isn't
+            # handled before that for pcolor calls.
+            kwargs.pop('shading', None)
         result = matplotlib.axes.Axes.pcolor(self, *args, **kwargs)
 
         # Update the datalim for this pcolor.

lib/cartopy/mpl/gridliner.py

@@ -796,8 +796,6 @@ def update_artist(artist, renderer):
         # Cache a few things so they aren't re-calculated in the loops.
         crs_transform = self._crs_transform().transform
         inverse_data_transform = self.axes.transData.inverted().transform_point
-        if self.x_inline or self.y_inline:
-            pc_transform = PlateCarree()
 
         for xylabel, lines, line_ticks, formatter, label_style in (
                 ('x', lon_lines, lon_ticks,
@@ -899,7 +897,7 @@ def update_artist(artist, renderer):
                     # Initial text specs
                     x0, y0 = pt0
                     if x_inline or y_inline:
-                        kw = {'rotation': 0, 'transform': pc_transform,
+                        kw = {'rotation': 0, 'transform': self.crs,
                               'ha': 'center', 'va': 'center'}
                         loc = 'inline'
                     else:

lib/cartopy/tests/mpl/test_mpl_integration.py

@@ -583,7 +583,7 @@ def test_pcolormesh_diagonal_wrap():
     # and the bottom edge on the other gets wrapped properly
     xs = [[160, 170], [190, 200]]
     ys = [[-10, -10], [10, 10]]
-    zs = [[0, 1], [0, 1]]
+    zs = [[0]]
 
     ax = plt.axes(projection=ccrs.PlateCarree())
     mesh = ax.pcolormesh(xs, ys, zs)
@@ -652,6 +652,31 @@ def test_pcolormesh_wrap_set_array():
     coll.set_array(Z.ravel())
 
 
+@pytest.mark.parametrize('shading, input_size, expected', [
+    pytest.param('auto', 3, 4, id='auto same size'),
+    pytest.param('auto', 4, 4, id='auto input larger'),
+    pytest.param('nearest', 3, 4, id='nearest same size'),
+    pytest.param('nearest', 4, 4, id='nearest input larger'),
+    pytest.param('flat', 4, 4, id='flat input larger'),
+    pytest.param('gouraud', 3, 3, id='gouraud same size')
+])
+def test_pcolormesh_shading(shading, input_size, expected):
+    # Testing that the coordinates are all broadcast as expected with
+    # the various shading options
+    # The data shape is (3, 3) and we are changing the input shape
+    # based upon that
+    ax = plt.axes(projection=ccrs.PlateCarree())
+
+    x = np.arange(input_size)
+    y = np.arange(input_size)
+    d = np.zeros((3, 3))
+
+    coll = ax.pcolormesh(x, y, d, shading=shading)
+    # We can use coll.get_coordinates() once MPL >= 3.5 is required
+    # For now, we use the private variable for testing
+    assert coll._coordinates.shape == (expected, expected, 2)
+
+
 @pytest.mark.natural_earth
 @ImageTesting(['quiver_plate_carree'])
 def test_quiver_plate_carree():
@@ -830,8 +855,10 @@ def test_barbs_1d_transformed():
 
 
 @pytest.mark.natural_earth
-@ImageTesting(['streamplot'], style='mpl20',
-              tolerance=42 if MPL_VERSION < parse_version('3.2') else 0.54)
+@ImageTesting(
+    ['streamplot'], style='mpl20',
+    tolerance=(42 if MPL_VERSION.release[:2] < (3, 2) else
+               9.77 if MPL_VERSION.release[:2] < (3, 5) else 0.5))
 def test_streamplot():
     x = np.arange(-60, 42.5, 2.5)
     y = np.arange(30, 72.5, 2.5)

lib/cartopy/tests/mpl/test_pseudo_color.py

@@ -14,7 +14,7 @@
 
 
 def test_pcolormesh_partially_masked():
-    data = np.ma.masked_all((40, 30))
+    data = np.ma.masked_all((39, 29))
     data[0:100] = 10
 
     # Check that a partially masked data array does trigger a pcolor call.
@@ -27,7 +27,7 @@ def test_pcolormesh_partially_masked():
 
 
 def test_pcolormesh_invisible():
-    data = np.zeros((3, 3))
+    data = np.zeros((2, 2))
 
     # Check that a fully invisible mesh doesn't fail.
     with mock.patch('cartopy.mpl.geoaxes.GeoAxes.pcolor') as pcolor:

lib/cartopy/tests/mpl/test_ticks.py

@@ -11,12 +11,8 @@
 from cartopy.tests.mpl import ImageTesting
 
 
-ticks_tolerance = 7
-
-
 @pytest.mark.natural_earth
-@ImageTesting(['xticks_no_transform'],
-              tolerance=ticks_tolerance)
+@ImageTesting(['xticks_no_transform'])
 def test_set_xticks_no_transform():
     ax = plt.axes(projection=ccrs.PlateCarree())
     ax.coastlines('110m')
@@ -26,12 +22,9 @@ def test_set_xticks_no_transform():
 
 
 @pytest.mark.natural_earth
-@ImageTesting(['xticks_cylindrical'],
-              tolerance=ticks_tolerance)
+@ImageTesting(['xticks_cylindrical'])
 def test_set_xticks_cylindrical():
-    ax = plt.axes(projection=ccrs.Mercator(
-                  min_latitude=-85.,
-                  max_latitude=85.))
+    ax = plt.axes(projection=ccrs.Mercator(min_latitude=-85, max_latitude=85))
     ax.coastlines('110m')
     ax.xaxis.set_major_formatter(LongitudeFormatter(degree_symbol=''))
     ax.set_xticks([-180, -90, 0, 90, 180], crs=ccrs.PlateCarree())
@@ -48,40 +41,38 @@ def test_set_xticks_non_cylindrical():
 
 
 @pytest.mark.natural_earth
-@ImageTesting(['yticks_no_transform'],
-              tolerance=ticks_tolerance)
+@ImageTesting(['yticks_no_transform'])
 def test_set_yticks_no_transform():
     ax = plt.axes(projection=ccrs.PlateCarree())
     ax.coastlines('110m')
     ax.yaxis.set_major_formatter(LatitudeFormatter(degree_symbol=''))
     ax.set_yticks([-60, -30, 0, 30, 60])
-    ax.set_yticks([-75, -45, 15, 45, 75], minor=True)
+    ax.set_yticks([-75, -45, -15, 15, 45, 75], minor=True)
 
 
 @pytest.mark.natural_earth
-@ImageTesting(['yticks_cylindrical'],
-              tolerance=ticks_tolerance)
+@ImageTesting(['yticks_cylindrical'])
 def test_set_yticks_cylindrical():
-    ax = plt.axes(projection=ccrs.Mercator(
-                  min_latitude=-85.,
-                  max_latitude=85.))
+    ax = plt.axes(projection=ccrs.Mercator(min_latitude=-85, max_latitude=85))
     ax.coastlines('110m')
     ax.yaxis.set_major_formatter(LatitudeFormatter(degree_symbol=''))
     ax.set_yticks([-60, -30, 0, 30, 60], crs=ccrs.PlateCarree())
-    ax.set_yticks([-75, -45, 15, 45, 75], minor=True, crs=ccrs.PlateCarree())
+    ax.set_yticks([-75, -45, -15, 15, 45, 75], minor=True,
+                  crs=ccrs.PlateCarree())
 
 
 def test_set_yticks_non_cylindrical():
     ax = plt.axes(projection=ccrs.Orthographic())
     with pytest.raises(RuntimeError):
         ax.set_yticks([-60, -30, 0, 30, 60], crs=ccrs.Geodetic())
     with pytest.raises(RuntimeError):
-        ax.set_yticks([-75, -45, 15, 45, 75], minor=True, crs=ccrs.Geodetic())
+        ax.set_yticks([-75, -45, -15, 15, 45, 75], minor=True,
+                      crs=ccrs.Geodetic())
     plt.close()
 
 
 @pytest.mark.natural_earth
-@ImageTesting(['xyticks'], tolerance=ticks_tolerance)
+@ImageTesting(['xyticks'])
 def test_set_xyticks():
     fig = plt.figure(figsize=(10, 10))
     projections = (ccrs.PlateCarree(),

lib/cartopy/tests/test_crs.py

@@ -6,6 +6,8 @@
 
 import copy
 from io import BytesIO
+import os
+from pathlib import Path
 import pickle
 
 import numpy as np
@@ -46,19 +48,31 @@ def test_osni(self, approx):
                              3)
 
     def _check_osgb(self, osgb):
+        precision = 1
+
+        if os.environ.get('PROJ_NETWORK') != 'ON':
+            grid_name = 'uk_os_OSTN15_NTv2_OSGBtoETRS.tif'
+            available = (
+                Path(pyproj.datadir.get_data_dir(), grid_name).exists() or
+                Path(pyproj.datadir.get_user_data_dir(), grid_name).exists()
+            )
+            if not available:
+                import warnings
+                warnings.warn(f'{grid_name} is unavailable; '
+                              'testing OSGB at reduced precision')
+                precision = -1
+
         ll = ccrs.Geodetic()
 
         # results obtained by streetmap.co.uk.
         lat, lon = np.array([50.462023, -3.478831], dtype=np.double)
         east, north = np.array([295132.1,  63512.6], dtype=np.double)
 
         # note the handling of precision here...
-        assert_arr_almost_eq(np.array(osgb.transform_point(lon, lat, ll)),
-                             np.array([east, north]),
-                             1)
-        assert_arr_almost_eq(ll.transform_point(east, north, osgb),
-                             [lon, lat],
-                             2)
+        assert_almost_equal(osgb.transform_point(lon, lat, ll), [east, north],
+                            decimal=precision)
+        assert_almost_equal(ll.transform_point(east, north, osgb), [lon, lat],
+                            decimal=2)
 
         r_lon, r_lat = ll.transform_point(east, north, osgb)
         r_inverted = np.array(osgb.transform_point(r_lon, r_lat, ll))

setup.py

@@ -26,11 +26,11 @@
 
 import fnmatch
 import os
+import shutil
 import subprocess
 import warnings
 from collections import defaultdict
-from distutils.spawn import find_executable
-from distutils.sysconfig import get_config_var
+from sysconfig import get_config_var
 
 from setuptools import Command, Extension, convert_path, setup
 
@@ -142,7 +142,7 @@ def find_package_tree(root_path, root_package):
 
 # Proj
 def find_proj_version_by_program(conda=None):
-    proj = find_executable('proj')
+    proj = shutil.which('proj')
     if proj is None:
         print(
             'Proj {} must be installed.'.format(

tools/cartopy_feature_download.py

@@ -64,6 +64,7 @@
         ('cultural', 'admin_0_pacific_groupings', '110m'),
         ('cultural', 'admin_1_states_provinces', '110m'),
         ('cultural', 'admin_1_states_provinces_lines', '110m'),
+        ('cultural', 'admin_1_states_provinces_lakes', ALL_SCALES),
     ),
 }