def city_from_extent(extent):
city_extents = dict([(m['short_name'], m['extent']) for m in METRO_LIST])
env = OGRGeometry(Envelope(*extent).wkt)
matches = []
for slug, city_ext in city_extents.iteritems():
city_env = OGRGeometry(Envelope(*city_ext).wkt)
if city_env.intersects(env):
matches.append((slug, city_env))
if len(matches) == 1:
return matches[0][0]
elif len(matches) > 1:
# Crudely select the intersecting city with the most overlap
# TODO: get rid of this
current_best_slug, current_max_area = None, float('-inf')
for slug, city_env in matches:
intersection = city_env.intersection(env)
area = intersection.area
if area > current_max_area:
current_max_area = area
current_best_slug = slug
return current_best_slug
# If we didn't find a match with a city extent, start expanding the buffer
# around the city extents until we match one
for i in xrange(6):
for slug, city_ext in city_extents.iteritems():
extent = buffer_extent(city_ext, 1, num_tiles=i+1)
city_env = OGRGeometry(Envelope(*extent).wkt)
if env.intersects(city_env):
return slug
def city_from_extent(extent):
city_extents = dict([(m['short_name'], m['extent']) for m in METRO_LIST])
env = OGRGeometry(Envelope(*extent).wkt)
matches = []
for slug, city_ext in city_extents.iteritems():
city_env = OGRGeometry(Envelope(*city_ext).wkt)
if city_env.intersects(env):
matches.append((slug, city_env))
if len(matches) == 1:
return matches[0][0]
elif len(matches) > 1:
# Crudely select the intersecting city with the most overlap
# TODO: get rid of this
current_best_slug, current_max_area = None, float('-inf')
for slug, city_env in matches:
intersection = city_env.intersection(env)
area = intersection.area
if area > current_max_area:
current_max_area = area
current_best_slug = slug
return current_best_slug
# If we didn't find a match with a city extent, start expanding the buffer
# around the city extents until we match one
for i in xrange(6):
for slug, city_ext in city_extents.iteritems():
extent = buffer_extent(city_ext, 1, num_tiles=i + 1)
city_env = OGRGeometry(Envelope(*extent).wkt)
if env.intersects(city_env):
return slug
def test_intersection(self):
"Testing intersects() and intersection()."
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)
i1 = OGRGeometry(self.geometries.intersect_geoms[i].wkt)
self.assertTrue(a.intersects(b))
i2 = a.intersection(b)
self.assertEqual(i1, i2)
self.assertEqual(i1, a & b) # __and__ is intersection operator
a &= b # testing __iand__
self.assertEqual(i1, a)
def test11_intersection(self):
"Testing intersects() and intersection()."
for i in xrange(len(self.geometries.topology_geoms)):
a = OGRGeometry(self.geometries.topology_geoms[i].wkt_a)
b = OGRGeometry(self.geometries.topology_geoms[i].wkt_b)
i1 = OGRGeometry(self.geometries.intersect_geoms[i].wkt)
self.assertEqual(True, a.intersects(b))
i2 = a.intersection(b)
self.assertEqual(i1, i2)
self.assertEqual(i1, a & b) # __and__ is intersection operator
a &= b # testing __iand__
self.assertEqual(i1, a)
def test11_intersection(self):
"Testing intersects() and intersection()."
for i in xrange(len(topology_geoms)):
g_tup = topology_geoms[i]
a = OGRGeometry(g_tup[0].wkt)
b = OGRGeometry(g_tup[1].wkt)
i1 = OGRGeometry(intersect_geoms[i].wkt)
self.assertEqual(True, a.intersects(b))
i2 = a.intersection(b)
self.assertEqual(i1, i2)
self.assertEqual(i1, a & b) # __and__ is intersection operator
a &= b # testing __iand__
self.assertEqual(i1, a)
def test_intersection(self):
"Testing intersects() and intersection()."
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)
i1 = OGRGeometry(self.geometries.intersect_geoms[i].wkt)
self.assertTrue(a.intersects(b))
i2 = a.intersection(b)
self.assertTrue(i1.geos.equals(i2.geos))
self.assertTrue(i1.geos.equals(
(a & b).geos)) # __and__ is intersection operator
a &= b # testing __iand__
self.assertTrue(i1.geos.equals(a.geos))
def read_node(f, filter_env, ids):
"""
Follows query_node() in plugins/input/shape/shp_index.hpp
"""
(offset,) = struct.unpack('i', f.read(4))
envelope = OGRGeometry(Envelope(*struct.unpack('4d', f.read(32))).wkt)
(shape_count,) = struct.unpack('i', f.read(4))
if not envelope.intersects(filter_env):
f.seek(offset + shape_count * 4 + 4, 1)
return
ids.extend(struct.unpack('%di' % shape_count, f.read(4 * shape_count)))
(num_children,) = struct.unpack('i', f.read(4))
for i in xrange(num_children):
read_node(f, filter_env, ids)
def pixel_value_from_point(raster, point, band=0):
"""
Returns the pixel value for the coordinate of the input point from selected
band.
The input can be a point or tuple, if its a tuple it is assumed to be
coordinates in the reference system of the raster.
"""
if isinstance(point, (tuple, list)):
point = OGRGeometry('POINT({0} {1})'.format(*point))
point.srid = raster.srid
elif not point.srs or not raster.srs:
raise ValueError(
'Both the point and the raster are required to have a reference system specified.'
)
elif point.srs != raster.srs:
# Ensure the projection of the point is the same as of the raster.
point.transform(raster.srid)
# Return if point and raster do not touch.
bbox = OGRGeometry.from_bbox(raster.extent)
bbox.srs = raster.srs
if not point.intersects(bbox):
return
# Compute position of point relative to raster origin.
offset = (abs(raster.origin.x - point.coords[0]),
abs(raster.origin.y - point.coords[1]))
# Compute pixel index value based on offset.
offset_index = [
int(offset[0] / abs(raster.scale.x)),
int(offset[1] / abs(raster.scale.y))
]
# If the point is exactly on the boundary, the offset_index is rounded to
# a pixel index over the edge of the pixel. The index needs to be reduced
# by one pixel for those cases.
if offset_index[0] == raster.width:
offset_index[0] -= 1
if offset_index[1] == raster.height:
offset_index[1] -= 1
return raster.bands[band].data(offset=offset_index, size=(1, 1))[0, 0]
def pixel_value_from_point(raster, point, band=0):
"""
Returns the pixel value for the coordinate of the input point from selected
band.
The input can be a point or tuple, if its a tuple it is assumed to be
coordinates in the reference system of the raster.
"""
if isinstance(point, (tuple, list)):
point = OGRGeometry('POINT({0} {1})'.format(*point))
point.srid = raster.srid
elif not point.srs or not raster.srs:
raise ValueError('Both the point and the raster are required to have a reference system specified.')
elif point.srs != raster.srs:
# Ensure the projection of the point is the same as of the raster.
point.transform(raster.srid)
# Return if point and raster do not touch.
bbox = OGRGeometry.from_bbox(raster.extent)
bbox.srs = raster.srs
if not point.intersects(bbox):
return
# Compute position of point relative to raster origin.
offset = (abs(raster.origin.x - point.coords[0]), abs(raster.origin.y - point.coords[1]))
# Compute pixel index value based on offset.
offset_index = [int(offset[0] / abs(raster.scale.x)), int(offset[1] / abs(raster.scale.y))]
# If the point is exactly on the boundary, the offset_index is rounded to
# a pixel index over the edge of the pixel. The index needs to be reduced
# by one pixel for those cases.
if offset_index[0] == raster.width:
offset_index[0] -= 1
if offset_index[1] == raster.height:
offset_index[1] -= 1
return raster.bands[band].data(offset=offset_index, size=(1, 1))[0, 0]
