forked from 170010011/fr
100 lines
3.0 KiB
Python
100 lines
3.0 KiB
Python
"""
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Support for GEOS prepared geometry operations.
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"""
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from shapely.geos import lgeos
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from shapely.impl import DefaultImplementation, delegated
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from pickle import PicklingError
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class PreparedGeometry(object):
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"""
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A geometry prepared for efficient comparison to a set of other geometries.
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Example:
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>>> from shapely.geometry import Point, Polygon
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>>> triangle = Polygon(((0.0, 0.0), (1.0, 1.0), (1.0, -1.0)))
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>>> p = prep(triangle)
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>>> p.intersects(Point(0.5, 0.5))
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True
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"""
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impl = DefaultImplementation
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def __init__(self, context):
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if isinstance(context, PreparedGeometry):
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self.context = context.context
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else:
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self.context = context
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self.__geom__ = lgeos.GEOSPrepare(self.context._geom)
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self.prepared = True
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def __del__(self):
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if self.__geom__ is not None:
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try:
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lgeos.GEOSPreparedGeom_destroy(self.__geom__)
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except AttributeError:
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pass # lgeos might be empty on shutdown.
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self.__geom__ = None
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self.context = None
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self.prepared = False
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@property
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def _geom(self):
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return self.__geom__
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@delegated
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def contains(self, other):
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"""Returns True if the geometry contains the other, else False"""
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return bool(self.impl['prepared_contains'](self, other))
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@delegated
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def contains_properly(self, other):
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"""Returns True if the geometry properly contains the other, else False"""
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return bool(self.impl['prepared_contains_properly'](self, other))
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@delegated
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def covers(self, other):
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"""Returns True if the geometry covers the other, else False"""
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return bool(self.impl['prepared_covers'](self, other))
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@delegated
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def crosses(self, other):
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"""Returns True if the geometries cross, else False"""
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return bool(self.impl['prepared_crosses'](self, other))
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@delegated
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def disjoint(self, other):
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"""Returns True if geometries are disjoint, else False"""
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return bool(self.impl['prepared_disjoint'](self, other))
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@delegated
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def intersects(self, other):
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"""Returns True if geometries intersect, else False"""
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return bool(self.impl['prepared_intersects'](self, other))
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@delegated
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def overlaps(self, other):
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"""Returns True if geometries overlap, else False"""
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return bool(self.impl['prepared_overlaps'](self, other))
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@delegated
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def touches(self, other):
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"""Returns True if geometries touch, else False"""
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return bool(self.impl['prepared_touches'](self, other))
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@delegated
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def within(self, other):
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"""Returns True if geometry is within the other, else False"""
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return bool(self.impl['prepared_within'](self, other))
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def __reduce__(self):
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raise PicklingError("Prepared geometries cannot be pickled.")
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def prep(ob):
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"""Creates and returns a prepared geometric object."""
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return PreparedGeometry(ob)
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