147 lines
3.9 KiB
Python
147 lines
3.9 KiB
Python
|
"""Collections of linestrings and related utilities
|
||
|
|
"""
|
||
|
|
|
||
|
|
import sys
|
||
|
|
|
||
|
|
if sys.version_info[0] < 3:
|
||
|
|
range = xrange
|
||
|
|
|
||
|
|
from ctypes import c_void_p, cast
|
||
|
|
|
||
|
|
from shapely.geos import lgeos
|
||
|
|
from shapely.geometry.base import BaseMultipartGeometry, geos_geom_from_py
|
||
|
|
from shapely.geometry import linestring
|
||
|
|
from shapely.geometry.proxy import CachingGeometryProxy
|
||
|
|
|
||
|
|
__all__ = ['MultiLineString', 'asMultiLineString']
|
||
|
|
|
||
|
|
|
||
|
|
class MultiLineString(BaseMultipartGeometry):
|
||
|
|
"""
|
||
|
|
A collection of one or more line strings
|
||
|
|
|
||
|
|
A MultiLineString has non-zero length and zero area.
|
||
|
|
|
||
|
|
Attributes
|
||
|
|
----------
|
||
|
|
geoms : sequence
|
||
|
|
A sequence of LineStrings
|
||
|
|
"""
|
||
|
|
|
||
|
|
def __init__(self, lines=None):
|
||
|
|
"""
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
lines : sequence
|
||
|
|
A sequence of line-like coordinate sequences or objects that
|
||
|
|
provide the numpy array interface, including instances of
|
||
|
|
LineString.
|
||
|
|
|
||
|
|
Example
|
||
|
|
-------
|
||
|
|
Construct a collection containing one line string.
|
||
|
|
|
||
|
|
>>> lines = MultiLineString( [[[0.0, 0.0], [1.0, 2.0]]] )
|
||
|
|
"""
|
||
|
|
super(MultiLineString, self).__init__()
|
||
|
|
|
||
|
|
if not lines:
|
||
|
|
# allow creation of empty multilinestrings, to support unpickling
|
||
|
|
pass
|
||
|
|
else:
|
||
|
|
self._geom, self._ndim = geos_multilinestring_from_py(lines)
|
||
|
|
|
||
|
|
def shape_factory(self, *args):
|
||
|
|
return linestring.LineString(*args)
|
||
|
|
|
||
|
|
@property
|
||
|
|
def __geo_interface__(self):
|
||
|
|
return {
|
||
|
|
'type': 'MultiLineString',
|
||
|
|
'coordinates': tuple(tuple(c for c in g.coords) for g in self.geoms)
|
||
|
|
}
|
||
|
|
|
||
|
|
def svg(self, scale_factor=1., stroke_color=None):
|
||
|
|
"""Returns a group of SVG polyline elements for the LineString geometry.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
==========
|
||
|
|
scale_factor : float
|
||
|
|
Multiplication factor for the SVG stroke-width. Default is 1.
|
||
|
|
stroke_color : str, optional
|
||
|
|
Hex string for stroke color. Default is to use "#66cc99" if
|
||
|
|
geometry is valid, and "#ff3333" if invalid.
|
||
|
|
"""
|
||
|
|
if self.is_empty:
|
||
|
|
return '<g />'
|
||
|
|
if stroke_color is None:
|
||
|
|
stroke_color = "#66cc99" if self.is_valid else "#ff3333"
|
||
|
|
return '<g>' + \
|
||
|
|
''.join(p.svg(scale_factor, stroke_color) for p in self) + \
|
||
|
|
'</g>'
|
||
|
|
|
||
|
|
|
||
|
|
class MultiLineStringAdapter(CachingGeometryProxy, MultiLineString):
|
||
|
|
|
||
|
|
context = None
|
||
|
|
_other_owned = False
|
||
|
|
|
||
|
|
def __init__(self, context):
|
||
|
|
self.context = context
|
||
|
|
self.factory = geos_multilinestring_from_py
|
||
|
|
|
||
|
|
@property
|
||
|
|
def _ndim(self):
|
||
|
|
try:
|
||
|
|
# From array protocol
|
||
|
|
array = self.context[0].__array_interface__
|
||
|
|
n = array['shape'][1]
|
||
|
|
assert n == 2 or n == 3
|
||
|
|
return n
|
||
|
|
except AttributeError:
|
||
|
|
# Fall back on list
|
||
|
|
return len(self.context[0][0])
|
||
|
|
|
||
|
|
|
||
|
|
def asMultiLineString(context):
|
||
|
|
"""Adapts a sequence of objects to the MultiLineString interface"""
|
||
|
|
return MultiLineStringAdapter(context)
|
||
|
|
|
||
|
|
|
||
|
|
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)
|
||
|
|
|
||
|
|
|
||
|
|
# Test runner
|
||
|
|
def _test():
|
||
|
|
import doctest
|
||
|
|
doctest.testmod()
|
||
|
|
|
||
|
|
if __name__ == "__main__":
|
||
|
|
_test()
|