# Small geometry processing

* changes SimpleGeomForm behaviour on small geometries (<1m²): These geometries will now be dismissed on processing
* adds a new info message in case of automatically removed geometries on saving
* updates tests

konova/forms/geometry_form.py

@@ -25,8 +25,8 @@ class SimpleGeomForm(BaseForm):
     """ A geometry form for rendering geometry read-only using a widget
 
     """
-    read_only = True
-    geometry_simplified = False
+    read_only: bool = True
+    _geometry_simplified: bool = False
     output = JSONField(
         label=_("Geometry"),
         help_text=_(""),
@@ -34,6 +34,7 @@ class SimpleGeomForm(BaseForm):
         required=False,
         disabled=False,
     )
+    _num_geometries_ignored: int = 0
 
     def __init__(self, *args, **kwargs):
         self.read_only = kwargs.pop("read_only", True)
@@ -48,6 +49,7 @@ class SimpleGeomForm(BaseForm):
                 raise AttributeError
 
             geojson = self.instance.geometry.as_feature_collection(srid=DEFAULT_SRID_RLP)
+            self._set_geojson_properties(geojson, title=self.instance.identifier or None)
             geom = json.dumps(geojson)
         except AttributeError:
             # If no geometry exists for this form, we simply set the value to None and zoom to the maximum level
@@ -61,7 +63,7 @@ class SimpleGeomForm(BaseForm):
         is_valid = True
 
         # Get geojson from form
-        geom = self.data["output"]
+        geom = self.data.get("output", None)
         if geom is None or len(geom) == 0:
             # empty geometry is a valid geometry
             self.cleaned_data["output"] = MultiPolygon(srid=DEFAULT_SRID_RLP).ewkt
@@ -100,7 +102,13 @@ class SimpleGeomForm(BaseForm):
                 is_valid &= False
                 return is_valid
 
-            is_valid &= self.__is_area_valid(g)
+            is_area_valid = self.__is_area_valid(g)
+            if not is_area_valid:
+                # Geometries with an invalid size will not be saved to the db
+                # We assume these are malicious snippets which are not supposed to be in the geometry in the first place
+                self._num_geometries_ignored += 1
+                continue
+
             g = Polygon.from_ewkt(g.ewkt)
             is_valid &= g.valid
             if not g.valid:
@@ -147,15 +155,6 @@ class SimpleGeomForm(BaseForm):
 
         """
         is_area_valid = geom.area > 1  # > 1m² (SRID:25832)
-
-        if not is_area_valid:
-            self.add_error(
-                "output",
-                _("Geometry must be greater than 1m². Currently is {}m²").format(
-                    float(geom.area)
-                )
-            )
-
         return is_area_valid
 
     def __simplify_geometry(self, geom, max_vert: int):
@@ -208,13 +207,29 @@ class SimpleGeomForm(BaseForm):
         if not is_vertices_num_valid:
             geometry.geom = self.__simplify_geometry(geometry.geom, max_vert=GEOM_MAX_VERTICES)
             geometry.save()
-            self.geometry_simplified = True
+            self._geometry_simplified = True
 
         # Start parcel update and geometry conflict checking procedure in a background process
         celery_update_parcels.delay(geometry.id)
         celery_check_for_geometry_conflicts.delay(geometry.id)
         return geometry
 
+    def get_num_geometries_ignored(self):
+        """ Returns the number of geometries which had to be ignored for various reasons
+
+        Returns:
+
+        """
+        return self._num_geometries_ignored
+
+    def has_geometry_simplified(self):
+        """ Returns whether the geometry has been simplified or not.
+
+        Returns:
+
+        """
+        return self._geometry_simplified
+
     def __flatten_geom_to_2D(self, geom):
         """
         Enforces a given OGRGeometry from higher dimensions into 2D
@@ -225,11 +240,12 @@ class SimpleGeomForm(BaseForm):
         geom = gdal.OGRGeometry(g_wkt)
         return geom
 
-    def _set_properties(self, geojson: dict, title: str):
+    def _set_geojson_properties(self, geojson: dict, title: str = None):
         """ Toggles the editable property of the geojson for proper handling in map client
 
         Args:
             geojson (dict): The GeoJson
+            title (str): An alternative title for the geometry
 
         Returns:
             geojson (dict): The altered GeoJson