DOC: comment why casting to list

SciTools · Nov 5, 2024 · 17f3899 · 17f3899
1 parent a8a18d1
commit 17f3899
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/lib/cartopy/mpl/slippy_image_artist.py b/lib/cartopy/mpl/slippy_image_artist.py
@@ -53,6 +53,9 @@ def draw(self, renderer, *args, **kwargs):
 
         ax = self.axes
         window_extent = ax.get_window_extent()
+        # We need to extract to a list to get native Python datatypes
+        # rather than Numpy datatypes since not all fetch_raster
+        # implementers handle Numpy datatypes properly.
         [x1, y1], [x2, y2] = ax.viewLim.get_points().tolist()
         if not self.user_is_interacting:
             located_images = self.raster_source.fetch_raster(