From 00cb9e13b4cf06ed2be27ee9e7fc18969ae69f7d Mon Sep 17 00:00:00 2001 From: Claude Paroz Date: Sat, 10 Oct 2015 19:22:42 +0200 Subject: [PATCH] Fixed #15165 -- Prevented wrong results with perimeter on geodetic fields. --- .../contrib/gis/db/backends/base/features.py | 3 ++- .../gis/db/backends/oracle/features.py | 1 + django/contrib/gis/db/models/functions.py | 20 +++++++++++++------ tests/gis_tests/distapp/tests.py | 18 +++++++++++++++++ 4 files changed, 35 insertions(+), 7 deletions(-) diff --git a/django/contrib/gis/db/backends/base/features.py b/django/contrib/gis/db/backends/base/features.py index 14eea12721..027baa5575 100644 --- a/django/contrib/gis/db/backends/base/features.py +++ b/django/contrib/gis/db/backends/base/features.py @@ -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 diff --git a/django/contrib/gis/db/backends/oracle/features.py b/django/contrib/gis/db/backends/oracle/features.py index b0b7e27df8..996fe8e54b 100644 --- a/django/contrib/gis/db/backends/oracle/features.py +++ b/django/contrib/gis/db/backends/oracle/features.py @@ -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 diff --git a/django/contrib/gis/db/models/functions.py b/django/contrib/gis/db/models/functions.py index 5b59e02f0b..17847bdc5c 100644 --- a/django/contrib/gis/db/models/functions.py +++ b/django/contrib/gis/db/models/functions.py @@ -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 diff --git a/tests/gis_tests/distapp/tests.py b/tests/gis_tests/distapp/tests.py index f9d3e7ecd8..9dbc4d3c11 100644 --- a/tests/gis_tests/distapp/tests.py +++ b/tests/gis_tests/distapp/tests.py @@ -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): """