def test_srs(self):
"Testing OGR Geometries with Spatial Reference objects."
for mp in self.geometries.multipolygons:
# Creating a geometry w/spatial reference
sr = SpatialReference('WGS84')
mpoly = OGRGeometry(mp.wkt, sr)
self.assertEqual(sr.wkt, mpoly.srs.wkt)
# Ensuring that SRS is propagated to clones.
klone = mpoly.clone()
self.assertEqual(sr.wkt, klone.srs.wkt)
# Ensuring all children geometries (polygons and their rings) all
# return the assigned spatial reference as well.
for poly in mpoly:
self.assertEqual(sr.wkt, poly.srs.wkt)
for ring in poly:
self.assertEqual(sr.wkt, ring.srs.wkt)
# Ensuring SRS propagate in topological ops.
a = OGRGeometry(self.geometries.topology_geoms[0].wkt_a, sr)
b = OGRGeometry(self.geometries.topology_geoms[0].wkt_b, sr)
diff = a.difference(b)
union = a.union(b)
self.assertEqual(sr.wkt, diff.srs.wkt)
self.assertEqual(sr.srid, union.srs.srid)
# Instantiating w/an integer SRID
mpoly = OGRGeometry(mp.wkt, 4326)
self.assertEqual(4326, mpoly.srid)
mpoly.srs = SpatialReference(4269)
self.assertEqual(4269, mpoly.srid)
self.assertEqual('NAD83', mpoly.srs.name)
# Incrementing through the multipolygon after the spatial reference
# has been re-assigned.
for poly in mpoly:
self.assertEqual(mpoly.srs.wkt, poly.srs.wkt)
poly.srs = 32140
for ring in poly:
# Changing each ring in the polygon
self.assertEqual(32140, ring.srs.srid)
self.assertEqual('NAD83 / Texas South Central',
ring.srs.name)
ring.srs = str(SpatialReference(4326)) # back to WGS84
self.assertEqual(4326, ring.srs.srid)
# Using the `srid` property.
ring.srid = 4322
self.assertEqual('WGS 72', ring.srs.name)
self.assertEqual(4322, ring.srid)
# srs/srid may be assigned their own values, even when srs is None.
mpoly = OGRGeometry(mp.wkt, srs=None)
mpoly.srs = mpoly.srs
mpoly.srid = mpoly.srid
def test_difference(self):
"Testing difference()."
for i in range(len(self.geometries.topology_geoms)):
a = OGRGeometry(self.geometries.topology_geoms[i].wkt_a)
b = OGRGeometry(self.geometries.topology_geoms[i].wkt_b)
d1 = OGRGeometry(self.geometries.diff_geoms[i].wkt)
d2 = a.difference(b)
self.assertEqual(d1, d2)
self.assertEqual(d1, a - b) # __sub__ is difference operator
a -= b # testing __isub__
self.assertEqual(d1, a)