def verify_geom(self, geom, model_field):
"""
Verify the geometry -- construct and return a GeometryCollection
if necessary (for example if the model field is MultiPolygonField while
the mapped shapefile only contains Polygons).
"""
# Downgrade a 3D geom to a 2D one, if necessary.
if self.coord_dim != geom.coord_dim:
geom.coord_dim = self.coord_dim
if self.make_multi(geom.geom_type, model_field):
# Constructing a multi-geometry type to contain the single geometry
multi_type = self.MULTI_TYPES[geom.geom_type.num]
g = OGRGeometry(multi_type)
g.add(geom)
else:
g = geom
# Transforming the geometry with our Coordinate Transformation object,
# but only if the class variable `transform` is set w/a CoordTransform
# object.
if self.transform:
g.transform(self.transform)
# Returning the WKT of the geometry.
return g.wkt
def test_transform_dim(self):
"Testing coordinate dimension is the same on transformed geometries."
ls_orig = OGRGeometry('LINESTRING(-104.609 38.255)', 4326)
ls_trans = OGRGeometry('LINESTRING(992385.4472045 481455.4944650)',
2774)
prec = 3
ls_orig.transform(ls_trans.srs)
# Making sure the coordinate dimension is still 2D.
self.assertEqual(2, ls_orig.coord_dim)
self.assertAlmostEqual(ls_trans.x[0], ls_orig.x[0], prec)
self.assertAlmostEqual(ls_trans.y[0], ls_orig.y[0], prec)
def test_ogrgeometry_transform_workaround(self):
"Testing coordinate dimensions on geometries after transformation."
# A bug in GDAL versions prior to 1.7 changes the coordinate
# dimension of a geometry after it has been transformed.
# This test ensures that the bug workarounds employed within
# `OGRGeometry.transform` indeed work.
wkt_2d = "MULTILINESTRING ((0 0,1 1,2 2))"
wkt_3d = "MULTILINESTRING ((0 0 0,1 1 1,2 2 2))"
srid = 4326
# For both the 2D and 3D MultiLineString, ensure _both_ the dimension
# of the collection and the component LineString have the expected
# coordinate dimension after transform.
geom = OGRGeometry(wkt_2d, srid)
geom.transform(srid)
self.assertEqual(2, geom.coord_dim)
self.assertEqual(2, geom[0].coord_dim)
self.assertEqual(wkt_2d, geom.wkt)
geom = OGRGeometry(wkt_3d, srid)
geom.transform(srid)
self.assertEqual(3, geom.coord_dim)
self.assertEqual(3, geom[0].coord_dim)
self.assertEqual(wkt_3d, geom.wkt)