do not set clip path for cartopy>=0.18 (#40)

* do not set clip path for cartopy>=0.18

* update changelog with fix for #37

CHANGELOG.rst

@@ -10,6 +10,8 @@ Fixed
 -----
 - psy-maps is now officially licensed under LGPL-3.0-only,
   see `#36 <https://github.com/psyplot/psy-maps/pull/36>`__
+- A bug has been resolved that crash makes unstructured plots fill the entire
+  area on zooming in, see `#40 <https://github.com/psyplot/psy-maps/pull/40>`__
 - psy-maps is now compatible with cartopy 0.19 and 0.20
 
 Changed

psy_maps/plotters.py

@@ -1774,8 +1774,6 @@ def _polycolor(self):
             self.ax.add_collection(self._plot)
             if cartopy.__version__ <= "0.18":
                 self._plot.set_clip_path(self.ax.outline_patch)
-            else:
-                self._plot.set_clip_path(self.ax.spines["geo"])
             if wrapped_arr is not None:
                 self.logger.debug('Making wrapped plot with %i cells',
                                   wrapped_arr.size)
@@ -1788,8 +1786,6 @@ def _polycolor(self):
                 self.ax.add_collection(self._wrapped_plot)
                 if cartopy.__version__ <= "0.18":
                     self._wrapped_plot.set_clip_path(self.ax.outline_patch)
-                else:
-                    self._wrapped_plot.set_clip_path(self.ax.spines["geo"])
         self.logger.debug('Done.')
 
     def remove(self, *args, **kwargs):