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_point_from_py(ob, update_geom=None, update_ndim=0):
"""Create a GEOS geom from an object that is a Point, a coordinate sequence
or that provides the array interface.
Returns the GEOS geometry and the number of its dimensions.
"""
if isinstance(ob, Point):
return geos_geom_from_py(ob)
# Accept either (x, y) or [(x, y)]
if not hasattr(ob, '__getitem__'): # Iterators, e.g. Python 3 zip
ob = list(ob)
if isinstance(ob[0], tuple):
coords = ob[0]
else:
coords = ob
n = len(coords)
dx = c_double(coords[0])
dy = c_double(coords[1])
dz = None
if n == 3:
dz = c_double(coords[2])
if update_geom:
cs = lgeos.GEOSGeom_getCoordSeq(update_geom)
if n != update_ndim:
raise ValueError(
"Wrong coordinate dimensions; this geometry has dimensions: "
"%d" % update_ndim)
else:
cs = lgeos.GEOSCoordSeq_create(1, n)
# Because of a bug in the GEOS C API, always set X before Y
lgeos.GEOSCoordSeq_setX(cs, 0, dx)
lgeos.GEOSCoordSeq_setY(cs, 0, dy)
if n == 3:
lgeos.GEOSCoordSeq_setZ(cs, 0, dz)
if update_geom:
return None
else:
return lgeos.GEOSGeom_createPoint(cs), 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