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- """
- This module houses the Geometry Collection objects:
- GeometryCollection, MultiPoint, MultiLineString, and MultiPolygon
- """
- from ctypes import byref, c_int, c_uint
- from django.contrib.gis.geos import prototypes as capi
- from django.contrib.gis.geos.geometry import GEOSGeometry, LinearGeometryMixin
- from django.contrib.gis.geos.libgeos import GEOM_PTR
- from django.contrib.gis.geos.linestring import LinearRing, LineString
- from django.contrib.gis.geos.point import Point
- from django.contrib.gis.geos.polygon import Polygon
- class GeometryCollection(GEOSGeometry):
- _typeid = 7
- def __init__(self, *args, **kwargs):
- "Initialize a Geometry Collection from a sequence of Geometry objects."
- # Checking the arguments
- if len(args) == 1:
- # If only one geometry provided or a list of geometries is provided
- # in the first argument.
- if isinstance(args[0], (tuple, list)):
- init_geoms = args[0]
- else:
- init_geoms = args
- else:
- init_geoms = args
- # Ensuring that only the permitted geometries are allowed in this collection
- # this is moved to list mixin super class
- self._check_allowed(init_geoms)
- # Creating the geometry pointer array.
- collection = self._create_collection(len(init_geoms), init_geoms)
- super().__init__(collection, **kwargs)
- def __iter__(self):
- "Iterate over each Geometry in the Collection."
- for i in range(len(self)):
- yield self[i]
- def __len__(self):
- "Return the number of geometries in this Collection."
- return self.num_geom
- # ### Methods for compatibility with ListMixin ###
- def _create_collection(self, length, items):
- # Creating the geometry pointer array.
- geoms = (GEOM_PTR * length)(*[
- # this is a little sloppy, but makes life easier
- # allow GEOSGeometry types (python wrappers) or pointer types
- capi.geom_clone(getattr(g, 'ptr', g)) for g in items
- ])
- return capi.create_collection(c_int(self._typeid), byref(geoms), c_uint(length))
- def _get_single_internal(self, index):
- return capi.get_geomn(self.ptr, index)
- def _get_single_external(self, index):
- "Return the Geometry from this Collection at the given index (0-based)."
- # Checking the index and returning the corresponding GEOS geometry.
- return GEOSGeometry(capi.geom_clone(self._get_single_internal(index)), srid=self.srid)
- def _set_list(self, length, items):
- "Create a new collection, and destroy the contents of the previous pointer."
- prev_ptr = self.ptr
- srid = self.srid
- self.ptr = self._create_collection(length, items)
- if srid:
- self.srid = srid
- capi.destroy_geom(prev_ptr)
- _set_single = GEOSGeometry._set_single_rebuild
- _assign_extended_slice = GEOSGeometry._assign_extended_slice_rebuild
- @property
- def kml(self):
- "Return the KML for this Geometry Collection."
- return '<MultiGeometry>%s</MultiGeometry>' % ''.join(g.kml for g in self)
- @property
- def tuple(self):
- "Return a tuple of all the coordinates in this Geometry Collection"
- return tuple(g.tuple for g in self)
- coords = tuple
- # MultiPoint, MultiLineString, and MultiPolygon class definitions.
- class MultiPoint(GeometryCollection):
- _allowed = Point
- _typeid = 4
- class MultiLineString(LinearGeometryMixin, GeometryCollection):
- _allowed = (LineString, LinearRing)
- _typeid = 5
- class MultiPolygon(GeometryCollection):
- _allowed = Polygon
- _typeid = 6
- # Setting the allowed types here since GeometryCollection is defined before
- # its subclasses.
- GeometryCollection._allowed = (Point, LineString, LinearRing, Polygon, MultiPoint, MultiLineString, MultiPolygon)
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