#49 Parcels and Districts

* fixes bug in GeometryConflict conflict checking
* WIP: introduces new konova/utils/wfs/spatial holding SpatialWFSFetcher, which can be fed any geometry and it returns found features
* WIP: adds tests for wfs fetching
* updates requirements.txt

konova/models/geometry.py

@@ -21,6 +21,7 @@ class Geometry(BaseResource):
     def save(self, *args, **kwargs):
         super().save(*args, **kwargs)
         self.check_for_conflicts()
+        self.update_parcels()
 
     def check_for_conflicts(self):
         """ Checks for new geometry overlaps
@@ -31,7 +32,7 @@ class Geometry(BaseResource):
 
         """
         # If no geometry is given or important data is missing, we can not perform any checks
-        if self.geom is None or (self.created is None and self.modified is None):
+        if self.geom is None:
             return None
 
         self.recheck_existing_conflicts()
@@ -43,7 +44,10 @@ class Geometry(BaseResource):
         ).distinct()
 
         for match in overlapping_geoms:
-            GeometryConflict.objects.get_or_create(conflicting_geometry=self, affected_geometry=match)
+            # Make sure this conflict is not already known but in a swapped constellation
+            conflict_exists_swapped = GeometryConflict.objects.filter(conflicting_geometry=match, affected_geometry=self).exists()
+            if not conflict_exists_swapped:
+                GeometryConflict.objects.get_or_create(conflicting_geometry=self, affected_geometry=match)
 
     def recheck_existing_conflicts(self):
         """ Rechecks GeometryConflict entries
@@ -88,6 +92,10 @@ class Geometry(BaseResource):
             objs += set_objs
         return objs
 
+    def update_parcels(self):
+        # ToDo
+        pass
+
 
 class GeometryConflict(UuidModel):
     """

konova/models/parcel.py

@@ -40,6 +40,7 @@ class Parcel(UuidModel):
         max_length=1000,
         help_text="Gemarkung"
     )
+    updated_on = models.DateTimeField(auto_now_add=True)
 
     def __str__(self):
         return f"{self.gmrkng} | {self.flr} | {self.flrstck_nnr} | {self.flrstck_zhlr}"

konova/tests/test_geometries.py

@@ -9,7 +9,7 @@ from django.contrib.gis.db.models.functions import Translate
 
 from konova.models import Geometry, GeometryConflict
 from konova.tests.test_views import BaseTestCase
-from user.models import UserActionLogEntry
+from konova.utils.wfs.spatial import SpatialWFSFetcher
 
 
 class GeometryTestCase(BaseTestCase):
@@ -17,14 +17,11 @@ class GeometryTestCase(BaseTestCase):
     def setUpTestData(cls):
         super().setUpTestData()
         geom = cls.create_dummy_geometry()
-        action = UserActionLogEntry.get_created_action(cls.superuser)
         cls.geom_1 = Geometry.objects.create(
             geom=geom,
-            created=action,
         )
         cls.geom_2 = Geometry.objects.create(
             geom=geom,
-            created=action,
         )
 
     def test_geometry_conflict(self):
@@ -34,8 +31,9 @@ class GeometryTestCase(BaseTestCase):
         Returns:
 
         """
-        self.geom_1.check_for_conflicts()
-        conflict = GeometryConflict.objects.all().first()
+        conflict = GeometryConflict.objects.all()
+        self.assertEqual(1, conflict.count())
+        conflict = conflict.first()
         self.assertEqual(conflict.conflicting_geometry, self.geom_2)
         self.assertEqual(conflict.affected_geometry, self.geom_1)
 
@@ -47,3 +45,21 @@ class GeometryTestCase(BaseTestCase):
         self.geom_1.check_for_conflicts()
         num_conflict = GeometryConflict.objects.all().count()
         self.assertEqual(0, num_conflict)
+
+    def test_wfs_fetch(self):
+        """ Tests the fetching functionality of SpatialWFSFetcher
+
+        +++ Test relies on the availability of the RLP Gemarkung WFS +++
+
+        Returns:
+
+        """
+        fetcher = SpatialWFSFetcher(
+            base_url="http://geo5.service24.rlp.de/wfs/verwaltungsgrenzen_rp.fcgi",
+            version="1.1.0",
+            geometry=self.geom_1
+        )
+        features = fetcher.get_features(
+            "vermkv:fluren_rlp"
+        )
+        self.assertNotEqual(0, len(features), msg="Spatial wfs get feature did not work!")

konova/utils/wfs/spatial.py

@@ -0,0 +1,92 @@
+"""
+Author: Michel Peltriaux
+Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
+Contact: michel.peltriaux@sgdnord.rlp.de
+Created on: 17.12.21
+
+"""
+from abc import abstractmethod
+
+import requests
+import xmltodict
+from django.contrib.gis.db.models.functions import AsGML, Transform
+from django.contrib.gis.geos import MultiPolygon
+from owslib.wfs import WebFeatureService
+
+from konova.models import Geometry
+from konova.settings import DEFAULT_SRID_RLP
+
+
+class BaseWFSFetcher:
+    # base_url represents not the capabilities url but the parameter-free base url
+    base_url = ""
+    version = ""
+    wfs = None
+
+    def __init__(self, base_url: str, version: str = "1.1.0", *args, **kwargs):
+        self.base_url = base_url
+        self.version = version
+        self.wfs = WebFeatureService(
+            url=base_url,
+            version=version,
+        )
+
+    @abstractmethod
+    def get_features(self, feature_identifier: str, filter: str):
+        raise NotImplementedError
+
+
+class SpatialWFSFetcher(BaseWFSFetcher):
+    """ Fetches features from a parcel WFS
+
+    """
+    geometry = None
+    geometry_property_name = ""
+
+    def __init__(self, geometry: MultiPolygon, geometry_property_name: str = "msGeometry", *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.geometry = geometry
+        self.geometry_property_name = geometry_property_name
+
+    def _create_geometry_filter(self, geometry_operation: str, filter_srid: str = None):
+        """ Creates an
+
+        Args:
+            geometry_operation ():
+            filter_srid ():
+
+        Returns:
+
+        """
+        if filter_srid is None:
+            filter_srid = DEFAULT_SRID_RLP
+        geom_gml = Geometry.objects.filter(
+            id=self.geometry.id
+        ).annotate(
+            transformed=Transform(srid=filter_srid, expression="geom")
+        ).annotate(
+            gml=AsGML('transformed')
+        ).first().gml
+        _filter = f"<Filter><{geometry_operation}><PropertyName>{self.geometry_property_name}</PropertyName>{geom_gml}</{geometry_operation}></Filter>"
+        return _filter
+
+    def get_features(self, typenames: str, geometry_operation: str = "Intersects", filter_srid: str = None, filter: str = None):
+        if filter is None:
+            filter = self._create_geometry_filter(geometry_operation, filter_srid)
+        response = requests.post(
+            url=f"{self.base_url}?request=GetFeature&service=WFS&version={self.version}&typenames={typenames}&count=10",
+            data={
+                "filter": filter,
+            }
+        )
+        content = response.content.decode("utf-8")
+        content = xmltodict.parse(content)
+        features = content.get(
+            "wfs:FeatureCollection",
+            {},
+        ).get(
+            "gml:featureMember",
+            [],
+        )
+        return features
+

requirements.txt

@@ -14,10 +14,14 @@ django-tables2==2.3.4
 et-xmlfile==1.1.0
 idna==2.10
 importlib-metadata==2.1.1
-itsdangerous<1.0.0
+itsdangerous==0.24
 openpyxl==3.0.9
+OWSLib==0.25.0
 psycopg2-binary==2.9.1
+pyproj==3.2.1
+python-dateutil==2.8.2
 pytz==2020.4
+PyYAML==6.0
 qrcode==7.3.1
 requests==2.25.0
 six==1.15.0
@@ -25,4 +29,5 @@ soupsieve==2.2.1
 sqlparse==0.4.1
 urllib3==1.26.2
 webservices==0.7
+xmltodict==0.12.0
 zipp==3.4.1