Handle empty SpatialUnit geometries, work-around for "POLYGON EMPTY" …

…geometries

cadasta/organization/importers/base.py

@@ -221,6 +221,9 @@ def _create_models(self, type, headers, row, content_types, tenure_type):
         if spatial_ct:
             try:
                 spatial_unit_id = row[headers.index(s_id)]
+            except ValueError:
+                su = SpatialUnit.objects.create(**spatial_ct)
+            else:
                 if spatial_unit_id:
                     created_su_id = self._locations_created.get(
                         spatial_unit_id, None
@@ -233,12 +236,13 @@ def _create_models(self, type, headers, row, content_types, tenure_type):
                 else:
                     su = SpatialUnit.objects.create(**spatial_ct)
                     self._locations_created[spatial_unit_id] = su.pk
-            except ValueError:
-                su = SpatialUnit.objects.create(**spatial_ct)
 
         if party_ct:
             try:
                 party_id = row[headers.index(p_id)]
+            except ValueError:
+                party = Party.objects.create(**party_ct)
+            else:
                 if party_id:
                     created_party_id = self._parties_created.get(
                         party_id, None)
@@ -250,8 +254,6 @@ def _create_models(self, type, headers, row, content_types, tenure_type):
                 else:
                     party = Party.objects.create(**party_ct)
                     self._parties_created[party_id] = party.pk
-            except ValueError:
-                party = Party.objects.create(**party_ct)
 
         if party_ct and spatial_ct:
             tt = TenureRelationshipType.objects.get(id=tenure_type)

cadasta/organization/importers/validators.py

@@ -1,11 +1,23 @@
+from functools import partial
+
 from django.contrib.gis.geos import GEOSGeometry
 from django.core.exceptions import ValidationError
 from django.utils.translation import ugettext as _
+
 from party.models import TenureRelationshipType
 from spatial.choices import TYPE_CHOICES
 from xforms.utils import InvalidODKGeometryError, odk_geom_to_wkt
 
 
+def get_field_value(headers, row, header, field_name):
+    try:
+        return row[headers.index(header)]
+    except ValueError:
+        raise ValidationError(
+            _("No '{}' column found.".format(field_name))
+        )
+
+
 def validate_row(headers, row, config):
     party_name, party_type, geometry, tenure_type, location_type = (
         None, None, None, None, None)
@@ -17,59 +29,40 @@ def validate_row(headers, row, config):
         raise ValidationError(
             _("Number of headers and columns do not match.")
         )
+
+    _get_field_value = partial(get_field_value, headers, row)
+
     if party_name_field and party_type_field:
-        try:
-            party_name = row[headers.index(party_name_field)]
-        except ValueError:
-            raise ValidationError(
-                _("No 'party_name' column found.")
-            )
-        try:
-            party_type = row[headers.index(party_type_field)]
-        except ValueError:
-            raise ValidationError(
-                _("No 'party_type' column found.")
-            )
+        party_name = _get_field_value(party_name_field, "party_name")
+        party_type = _get_field_value(party_type_field, "party_type")
+
     if geometry_field:
-        try:
-            coords = row[headers.index(geometry_field)]
-        except ValueError:
-            raise ValidationError(
-                _("No 'geometry_field' column found.")
-            )
-        try:
-            geometry = GEOSGeometry(coords)
-        except:
-            pass  # try ODK geom parser
-        if not geometry:
+        coords = _get_field_value(geometry_field, "geometry_field")
+        if coords == '':
+            geometry = None
+        else:
             try:
-                geometry = odk_geom_to_wkt(coords)
-            except InvalidODKGeometryError:
-                raise ValidationError(_("Invalid geometry."))
+                geometry = GEOSGeometry(coords)
+            except:
+                try:
+                    geometry = GEOSGeometry(odk_geom_to_wkt(coords))
+                except InvalidODKGeometryError:
+                    raise ValidationError(_("Invalid geometry."))
+
     if location_type_field:
-        try:
-            location_type = row[headers.index(location_type_field)]
-            type_choices = [choice[0] for choice in TYPE_CHOICES]
-            if location_type and location_type not in type_choices:
-                raise ValidationError(
-                    _("Invalid location_type: '%s'.") % location_type
-                )
-        except ValueError:
+        location_type = _get_field_value(location_type_field, "location_type")
+        type_choices = [choice[0] for choice in TYPE_CHOICES]
+        if location_type and location_type not in type_choices:
             raise ValidationError(
-                _("No 'location_type' column found.")
+                _("Invalid location_type: '%s'.") % location_type
             )
+
     if party_name_field and geometry_field:
-        try:
-            tenure_type = row[
-                headers.index(tenure_type_field)]
-            if tenure_type and not TenureRelationshipType.objects.filter(
-                    id=tenure_type).exists():
-                raise ValidationError(
-                    _("Invalid tenure_type: '%s'.") % tenure_type
-                )
-        except ValueError:
+        tenure_type = _get_field_value(tenure_type_field, 'tenure_type')
+        if tenure_type and not TenureRelationshipType.objects.filter(
+                id=tenure_type).exists():
             raise ValidationError(
-                _("No 'tenure_type' column found.")
+                _("Invalid tenure_type: '%s'.") % tenure_type
             )
 
     return (party_name, party_type, geometry, location_type, tenure_type)

cadasta/organization/tests/test_importers.py

@@ -170,6 +170,18 @@ def test_validate_geometry(self):
                 headers, row, config)
         assert e.value.message == "Invalid geometry."
 
+    def test_validate_empty_geometry(self):
+        config = {
+            'party_type_field': 'party_type',
+            'geometry_field': 'location_geometry',
+            'type': 'csv'
+        }
+        geometry = 'POLYGON EMPTY'
+        headers = ['party_type', 'location_geometry']
+        row = ['IN', geometry]
+        _, _, geo, _, _ = validators.validate_row(headers, row, config)
+        assert geo.empty is True
+
     def test_validate_location_type_choice(self):
         config = {
             'party_name_field': 'party_name',

cadasta/spatial/models.py

@@ -143,7 +143,16 @@ def reassign_spatial_geometry(instance):
 
 @receiver(models.signals.pre_save, sender=SpatialUnit)
 def check_extent(sender, instance, **kwargs):
-    if instance.geometry:
+    geom = instance.geometry
+    # Store 'POLYGON EMPTY' data as null to avoid libgeos bug
+    # (https://trac.osgeo.org/geos/ticket/680)
+    # TODO: Rm this check when we're using Django 1.11+ or libgeos 3.6.1+
+    # https://github.com/django/django/commit/b90d72facf1e4294df1c2e6b51b26f6879bf2992#diff-181a3ea304dfaf57f1e1d680b32d2b76R248
+    from django.contrib.gis.geos.polygon import Polygon
+    if isinstance(geom, Polygon) and geom.empty:
+        instance.geometry = None
+
+    if geom and not geom.empty:
         reassign_spatial_geometry(instance)
 
 

cadasta/spatial/tests/test_models.py

@@ -1,5 +1,6 @@
 import pytest
 
+from django.contrib.gis.geos import GEOSGeometry
 from django.contrib.contenttypes.models import ContentType
 from django.test import TestCase
 from jsonattrs.models import Attribute, AttributeType, Schema
@@ -44,6 +45,28 @@ def test_geometry(self):
             '11.36667 47.25000))')
         assert spatial_unit.geometry is not None
 
+    def test_empty_geometries(self):
+        geoms = (
+            "POINT EMPTY",
+            # "POLYGON EMPTY",  # Uncomment when using Django 1.11+ or libgeos 3.6.1+
+            "LINESTRING EMPTY",
+            "MULTIPOINT EMPTY",
+            "MULTILINESTRING EMPTY",
+            "MULTIPOLYGON EMPTY",
+            "GEOMETRYCOLLECTION EMPTY",
+        )
+        for geom in geoms:
+            spatial_unit = SpatialUnitFactory.create(
+                geometry=GEOSGeometry(geom))
+            assert spatial_unit.geometry.wkt == geom
+
+    def test_empty_geometry(self):
+        # Temp workaround where 'POLYGON EMPTY' is cast to None. Should
+        # be removed when Django is 1.11+ or libgeos is 3.6.1+
+        spatial_unit = SpatialUnitFactory.create(
+            geometry=GEOSGeometry('POLYGON EMPTY'))
+        assert spatial_unit.geometry is None
+
     def test_reassign_extent(self):
         spatial_unit = SpatialUnitFactory.create(
             geometry='SRID=4326;POLYGON(('