# Geometry form fix

* fixes bugs in tests
* refactors and simplifies geometry merging on GeometryForm

konova/forms/geometry_form.py

@@ -72,9 +72,8 @@ class SimpleGeomForm(BaseForm):
         # will be rendered again on failed submit
         self.initialize_form_field("geom", self.data["geom"])
 
-        # Read geojson into gdal geometry
-        # HINT: This can be simplified if the geojson format holds data in epsg:4326 (GDAL provides direct creation for
-        # this case)
+        # Initialize features list with empty MultiPolygon, so that an empty input will result in a
+        # proper empty MultiPolygon object
         features = []
         features_json = geom.get("features", [])
         accepted_ogr_types = [
@@ -102,19 +101,22 @@ class SimpleGeomForm(BaseForm):
                 return is_valid
 
             is_valid &= self.__is_area_valid(g)
-
-            polygon = Polygon.from_ewkt(g.ewkt)
-            is_valid &= polygon.valid
-            if not polygon.valid:
-                self.add_error("geom", polygon.valid_reason)
+            g = Polygon.from_ewkt(g.ewkt)
+            is_valid &= g.valid
+            if not g.valid:
+                self.add_error("geom", g.valid_reason)
                 return is_valid
 
-            features.append(polygon)
+            if isinstance(g, Polygon):
+                features.append(g)
+            elif isinstance(g, MultiPolygon):
+                features.extend(list(g))
 
         # Unionize all geometry features into one new MultiPolygon
-        form_geom = MultiPolygon(srid=DEFAULT_SRID_RLP)
-        for feature in features:
-            form_geom = form_geom.union(feature)
+        if features:
+            form_geom = MultiPolygon(*features, srid=DEFAULT_SRID_RLP).unary_union
+        else:
+            form_geom = MultiPolygon(srid=DEFAULT_SRID_RLP)
 
         # Make sure to convert into a MultiPolygon. Relevant if a single Polygon is provided.
         form_geom = Geometry.cast_to_multipolygon(form_geom)