80 lines
2.0 KiB
Python
80 lines
2.0 KiB
Python
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"""Multi-part collections of geometries
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"""
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from ctypes import c_void_p
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from shapely.geos import lgeos
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from shapely.geometry.base import BaseGeometry
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from shapely.geometry.base import BaseMultipartGeometry
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from shapely.geometry.base import HeterogeneousGeometrySequence
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from shapely.geometry.base import geos_geom_from_py
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class GeometryCollection(BaseMultipartGeometry):
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"""A heterogenous collection of geometries
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Attributes
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----------
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geoms : sequence
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A sequence of Shapely geometry instances
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"""
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def __init__(self, geoms=None):
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"""
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Parameters
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----------
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geoms : list
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A list of shapely geometry instances, which may be heterogenous.
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Example
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-------
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Create a GeometryCollection with a Point and a LineString
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>>> p = Point(51, -1)
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>>> l = LineString([(52, -1), (49, 2)])
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>>> gc = GeometryCollection([p, l])
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"""
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BaseMultipartGeometry.__init__(self)
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if not geoms:
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pass
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else:
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self._geom, self._ndim = geos_geometrycollection_from_py(geoms)
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@property
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def __geo_interface__(self):
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geometries = []
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for geom in self.geoms:
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geometries.append(geom.__geo_interface__)
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return dict(type='GeometryCollection', geometries=geometries)
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@property
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def geoms(self):
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if self.is_empty:
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return []
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return HeterogeneousGeometrySequence(self)
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def geos_geometrycollection_from_py(ob):
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"""Creates a GEOS GeometryCollection from a list of geometries"""
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L = len(ob)
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N = 2
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subs = (c_void_p * L)()
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for l in range(L):
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assert(isinstance(ob[l], BaseGeometry))
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if ob[l].has_z:
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N = 3
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geom, n = geos_geom_from_py(ob[l])
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subs[l] = geom
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return (lgeos.GEOSGeom_createCollection(7, subs, L), N)
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# Test runner
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def _test():
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import doctest
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doctest.testmod()
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if __name__ == "__main__":
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_test()
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