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108 | """
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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