def geos_multilinestring_from_py(ob):
# ob must be either a MultiLineString, a sequence, or
# array of sequences or arrays
if isinstance(ob, MultiLineString):
return geos_geom_from_py(ob)
obs = getattr(ob, 'geoms', ob)
L = len(obs)
assert L >= 1
exemplar = obs[0]
try:
N = len(exemplar[0])
except TypeError:
N = exemplar._ndim
if N not in (2, 3):
raise ValueError("Invalid coordinate dimensionality")
# Array of pointers to point geometries
subs = (c_void_p * L)()
# add to coordinate sequence
for l in range(L):
geom, ndims = linestring.geos_linestring_from_py(obs[l])
subs[l] = cast(geom, c_void_p)
return (lgeos.GEOSGeom_createCollection(5, subs, L), N)
def geos_multipolygon_from_polygons(arg):
"""Creates a GEOS multipolygon from a sequence of polygon-like objects.
Parameters
----------
arg : sequence or MultiPolygon
Returns
-------
int
Pointer to a GEOS multipolygon.
"""
if isinstance(arg, MultiPolygon):
return geos_geom_from_py(arg)
obs = getattr(arg, 'geoms', arg)
obs = [
ob for ob in obs
if ob and not (isinstance(ob, polygon.Polygon) and ob.is_empty)
]
L = len(obs)
# Bail immediately if we have no input points.
if L <= 0:
return (lgeos.GEOSGeom_createEmptyCollection(6), 3)
# This function does not accept sequences of MultiPolygons: there is
# no implicit flattening.
if isinstance(obs[0], MultiPolygon):
raise ValueError("Sequences of multi-polygons are not valid arguments")
exemplar = obs[0]
try:
N = len(exemplar[0][0])
except TypeError:
N = exemplar._ndim
assert N == 2 or N == 3
subs = (c_void_p * L)()
for i, ob in enumerate(obs):
if isinstance(ob, polygon.Polygon):
shell = ob.exterior
holes = ob.interiors
else:
shell = ob[0]
holes = ob[1]
geom, ndims = polygon.geos_polygon_from_py(shell, holes)
subs[i] = cast(geom, c_void_p)
return (lgeos.GEOSGeom_createCollection(6, subs, L), N)
def geos_geometrycollection_from_py(ob):
"""Creates a GEOS GeometryCollection from a list of geometries"""
L = len(ob)
N = 2
subs = (c_void_p * L)()
for l in range(L):
assert (isinstance(ob[l], BaseGeometry))
if ob[l].has_z:
N = 3
geom, n = geos_geom_from_py(ob[l])
subs[l] = geom
return (lgeos.GEOSGeom_createCollection(7, subs, L), N)
def geos_multipolygon_from_py(ob):
"""ob must provide Python geo interface coordinates."""
L = len(ob)
assert L >= 1
N = len(ob[0][0][0])
assert N == 2 or N == 3
subs = (c_void_p * L)()
for l in range(L):
geom, ndims = polygon.geos_polygon_from_py(ob[l][0], ob[l][1:])
subs[l] = cast(geom, c_void_p)
return (lgeos.GEOSGeom_createCollection(6, subs, L), N)
def geos_multipoint_from_py(ob):
if isinstance(ob, MultiPoint):
return geos_geom_from_py(ob)
m = len(ob)
try:
n = len(ob[0])
except TypeError:
n = ob[0]._ndim
assert n == 2 or n == 3
# Array of pointers to point geometries
subs = (c_void_p * m)()
# add to coordinate sequence
for i in range(m):
coords = ob[i]
geom, ndims = point.geos_point_from_py(coords)
subs[i] = cast(geom, c_void_p)
return lgeos.GEOSGeom_createCollection(4, subs, m), n