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