add comment about filtering geometry columns

Author: emanuel-schmid

climada/hazard/centroids/centr.py

@@ -915,6 +915,10 @@ def write_hdf5(self, file_name, mode="w"):
         store = pd.HDFStore(file_name, mode=mode, complevel=9)
         try:
             pandas_df = pd.DataFrame(self.gdf)
+            # we replace all columns of type geometry
+            # - with according x and y columns if they are strictly `Point`s
+            # - with wkb values if they have other shapes
+            # this saves a lot of time and disk space
             for col in pandas_df.columns:
                 if str(pandas_df[col].dtype) == "geometry":
                     if (self.gdf[col].geom_type == "Point").all():

climada/hazard/centroids/test/test_centr.py

@@ -767,7 +767,7 @@ def test_read_write_hdf5_with_additional_columns(self):
         )
         centroids_w.write_hdf5(tmpfile)
         centroids_r = Centroids.from_hdf5(tmpfile)
-        self.assertTrue(centroids_w == centroids_r)
+        self.assertEqual(centroids_w, centroids_r)
         tmpfile.unlink()
 
     def test_from_hdf5_nonexistent_file(self):