106 lines
4.1 KiB
Python
106 lines
4.1 KiB
Python
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"""
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This module houses the Geometry Collection objects:
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GeometryCollection, MultiPoint, MultiLineString, and MultiPolygon
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"""
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from ctypes import c_int, c_uint, byref
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from types import TupleType, ListType
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from django.contrib.gis.geos.base import GEOSGeometry
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from django.contrib.gis.geos.error import GEOSException, GEOSIndexError
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from django.contrib.gis.geos.geometries import Point, LineString, LinearRing, Polygon
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from django.contrib.gis.geos.libgeos import get_pointer_arr, GEOM_PTR
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from django.contrib.gis.geos.prototypes import create_collection, destroy_geom, geom_clone, geos_typeid, get_cs, get_geomn
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class GeometryCollection(GEOSGeometry):
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_allowed = (Point, LineString, LinearRing, Polygon)
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_typeid = 7
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def __init__(self, *args, **kwargs):
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"Initializes a Geometry Collection from a sequence of Geometry objects."
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# Checking the arguments
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if not args:
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raise TypeError, 'Must provide at least one Geometry to initialize %s.' % self.__class__.__name__
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if len(args) == 1:
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# If only one geometry provided or a list of geometries is provided
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# in the first argument.
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if isinstance(args[0], (TupleType, ListType)):
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init_geoms = args[0]
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else:
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init_geoms = args
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else:
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init_geoms = args
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# Ensuring that only the permitted geometries are allowed in this collection
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if False in [isinstance(geom, self._allowed) for geom in init_geoms]:
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raise TypeError('Invalid Geometry type encountered in the arguments.')
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# Creating the geometry pointer array.
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ngeoms = len(init_geoms)
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geoms = get_pointer_arr(ngeoms)
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for i in xrange(ngeoms): geoms[i] = geom_clone(init_geoms[i].ptr)
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super(GeometryCollection, self).__init__(create_collection(c_int(self._typeid), byref(geoms), c_uint(ngeoms)), **kwargs)
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def __getitem__(self, index):
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"Returns the Geometry from this Collection at the given index (0-based)."
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# Checking the index and returning the corresponding GEOS geometry.
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self._checkindex(index)
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return GEOSGeometry(geom_clone(get_geomn(self.ptr, index)), srid=self.srid)
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def __setitem__(self, index, geom):
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"Sets the Geometry at the specified index."
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self._checkindex(index)
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if not isinstance(geom, self._allowed):
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raise TypeError('Incompatible Geometry for collection.')
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ngeoms = len(self)
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geoms = get_pointer_arr(ngeoms)
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for i in xrange(ngeoms):
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if i == index:
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geoms[i] = geom_clone(geom.ptr)
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else:
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geoms[i] = geom_clone(get_geomn(self.ptr, i))
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# Creating a new collection, and destroying the contents of the previous poiner.
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prev_ptr = self.ptr
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srid = self.srid
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self._ptr = create_collection(c_int(self._typeid), byref(geoms), c_uint(ngeoms))
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if srid: self.srid = srid
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destroy_geom(prev_ptr)
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def __iter__(self):
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"Iterates over each Geometry in the Collection."
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for i in xrange(len(self)):
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yield self.__getitem__(i)
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def __len__(self):
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"Returns the number of geometries in this Collection."
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return self.num_geom
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def _checkindex(self, index):
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"Checks the given geometry index."
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if index < 0 or index >= self.num_geom:
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raise GEOSIndexError('invalid GEOS Geometry index: %s' % str(index))
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@property
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def kml(self):
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"Returns the KML for this Geometry Collection."
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return '<MultiGeometry>%s</MultiGeometry>' % ''.join([g.kml for g in self])
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@property
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def tuple(self):
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"Returns a tuple of all the coordinates in this Geometry Collection"
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return tuple([g.tuple for g in self])
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coords = tuple
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# MultiPoint, MultiLineString, and MultiPolygon class definitions.
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class MultiPoint(GeometryCollection):
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_allowed = Point
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_typeid = 4
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class MultiLineString(GeometryCollection):
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_allowed = (LineString, LinearRing)
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_typeid = 5
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class MultiPolygon(GeometryCollection):
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_allowed = Polygon
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_typeid = 6
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