FIX: close the path on GeoSpines around the boundary

lib/cartopy/mpl/geoaxes.py

@@ -262,7 +262,6 @@ def __init__(self, axes, **kwargs):
         self._original_path = mpath.Path(np.empty((0, 2)))
         kwargs.setdefault('clip_on', False)
         super().__init__(axes, 'geo', self._original_path, **kwargs)
-        self.set_capstyle('butt')
 
     def set_boundary(self, path, transform):
         self._original_path = path
@@ -272,6 +271,7 @@ def set_boundary(self, path, transform):
     def _adjust_location(self):
         if self.stale:
             self._path = self._original_path.clip_to_bbox(self.axes.viewLim)
+            self._path = mpath.Path(self._path.vertices, closed=True)
 
     def get_window_extent(self, renderer=None):
         # make sure the location is updated so that transforms etc are

lib/cartopy/tests/mpl/test_images.py

@@ -69,7 +69,7 @@ def test_web_tiles():
 
 @pytest.mark.natural_earth
 @pytest.mark.network
-@pytest.mark.mpl_image_compare(filename='image_merge.png', tolerance=0.01)
+@pytest.mark.mpl_image_compare(filename='image_merge.png', tolerance=0.03)
 def test_image_merge():
     # tests the basic image merging functionality
     tiles = []

lib/cartopy/tests/mpl/test_web_services.py

@@ -14,7 +14,7 @@
 @pytest.mark.filterwarnings("ignore:TileMatrixLimits")
 @pytest.mark.network
 @pytest.mark.skipif(not _OWSLIB_AVAILABLE, reason='OWSLib is unavailable.')
-@pytest.mark.mpl_image_compare(filename='wmts.png', tolerance=0)
+@pytest.mark.mpl_image_compare(filename='wmts.png', tolerance=0.03)
 def test_wmts():
     ax = plt.axes(projection=ccrs.PlateCarree())
     url = 'https://map1c.vis.earthdata.nasa.gov/wmts-geo/wmts.cgi'