Commit 00cb9e13 authored by Claude Paroz's avatar Claude Paroz Committed by Tim Graham
Browse files

Fixed #15165 -- Prevented wrong results with perimeter on geodetic fields.

parent e0519301

django/contrib/gis/db/backends/base/features.py

+2 −1
Original line number Diff line number Diff line
@@ -26,9 +26,10 @@ class BaseSpatialFeatures(object): 
    supports_real_shape_operations = True

    # Can geometry fields be null?

    supports_null_geometries = True

    # Can the `distance`/`length` functions be applied on geodetic coordinate systems?

    # Can the the function be applied on geodetic coordinate systems?

    supports_distance_geodetic = True

    supports_length_geodetic = True

    supports_perimeter_geodetic = False

    # Is the database able to count vertices on polygons (with `num_points`)?

    supports_num_points_poly = True

django/contrib/gis/db/backends/oracle/features.py

+1 −0
Original line number Diff line number Diff line
@@ -7,3 +7,4 @@ class DatabaseFeatures(BaseSpatialFeatures, OracleDatabaseFeatures): 
    supports_add_srs_entry = False

    supports_geometry_field_introspection = False

    supports_geometry_field_unique_index = False

    supports_perimeter_geodetic = True

django/contrib/gis/db/models/functions.py

+14 −6
Original line number Diff line number Diff line
@@ -206,6 +206,9 @@ class Difference(OracleToleranceMixin, GeoFuncWithGeoParam): 




class DistanceResultMixin(object):

    def source_is_geography(self):

        return self.get_source_fields()[0].geography and self.srid == 4326



    def convert_value(self, value, expression, connection, context):

        if value is None:

            return None
@@ -236,9 +239,7 @@ class Distance(DistanceResultMixin, OracleToleranceMixin, GeoFuncWithGeoParam): 


    def as_postgresql(self, compiler, connection):

        geo_field = GeometryField(srid=self.srid)  # Fake field to get SRID info

        src_field = self.get_source_fields()[0]

        geography = src_field.geography and self.srid == 4326

        if geography:

        if self.source_is_geography():

            # Set parameters as geography if base field is geography

            for pos, expr in enumerate(

                    self.source_expressions[self.geom_param_pos + 1:], start=self.geom_param_pos + 1):
@@ -297,9 +298,7 @@ class Length(DistanceResultMixin, OracleToleranceMixin, GeoFunc): 


    def as_postgresql(self, compiler, connection):

        geo_field = GeometryField(srid=self.srid)  # Fake field to get SRID info

        src_field = self.get_source_fields()[0]

        geography = src_field.geography and self.srid == 4326

        if geography:

        if self.source_is_geography():

            self.source_expressions.append(Value(self.spheroid))

        elif geo_field.geodetic(connection):

            # Geometry fields with geodetic (lon/lat) coordinates need length_spheroid
@@ -346,11 +345,20 @@ class Perimeter(DistanceResultMixin, OracleToleranceMixin, GeoFunc): 
    arity = 1



    def as_postgresql(self, compiler, connection):

        geo_field = GeometryField(srid=self.srid)  # Fake field to get SRID info

        if geo_field.geodetic(connection) and not self.source_is_geography():

            raise NotImplementedError("ST_Perimeter cannot use a non-projected non-geography field.")

        dim = min(f.dim for f in self.get_source_fields())

        if dim > 2:

            self.function = connection.ops.perimeter3d

        return super(Perimeter, self).as_sql(compiler, connection)



    def as_sqlite(self, compiler, connection):

        geo_field = GeometryField(srid=self.srid)  # Fake field to get SRID info

        if geo_field.geodetic(connection):

            raise NotImplementedError("Perimeter cannot use a non-projected field.")

        return super(Perimeter, self).as_sql(compiler, connection)





class PointOnSurface(OracleToleranceMixin, GeoFunc):

    arity = 1

tests/gis_tests/distapp/tests.py

+18 −0
Original line number Diff line number Diff line
@@ -444,6 +444,8 @@ Distance_Sphere(geom1, geom2) | N/A | OK (meter 


Distance_Spheroid(geom1, geom2, spheroid)     |    N/A             |   OK (meters)    |    N/A



ST_Perimeter(geom1)                           |    OK              |   :-( (degrees)  |    OK





================================

Distance functions on Spatialite
@@ -457,6 +459,8 @@ ST_Distance(geom1, geom2, use_ellipsoid=True) | N/A | OK ( 


ST_Distance(geom1, geom2, use_ellipsoid=False)  |    N/A             |      OK (meters), less accurate, quick



Perimeter(geom1)                                |    OK              |      :-( (degrees)



'''  # NOQA
@@ -688,6 +692,20 @@ class DistanceFunctionsTests(TestCase): 
        for city in qs:

            self.assertEqual(0, city.perim.m)



    @skipUnlessDBFeature("has_Perimeter_function")

    def test_perimeter_geodetic(self):

        # Currently only Oracle supports calculating the perimeter on geodetic

        # geometries (without being transformed).

        qs1 = CensusZipcode.objects.annotate(perim=Perimeter('poly'))

        if connection.features.supports_perimeter_geodetic:

            self.assertAlmostEqual(qs1[0].perim.m, 18406.3818954314, 3)

        else:

            with self.assertRaises(NotImplementedError):

                list(qs1)

        # But should work fine when transformed to projected coordinates

        qs2 = CensusZipcode.objects.annotate(perim=Perimeter(Transform('poly', 32140))).filter(name='77002')

        self.assertAlmostEqual(qs2[0].perim.m, 18404.355, 3)



    @skipUnlessDBFeature("supports_null_geometries", "has_Area_function", "has_Distance_function")

    def test_measurement_null_fields(self):

        """