1 """

     2  This module houses the Geometry Collection objects:

     3  GeometryCollection, MultiPoint, MultiLineString, and MultiPolygon

     4 """

     5 from ctypes import c_int, c_uint, byref

     6 from types import TupleType, ListType

     7 from django.contrib.gis.geos.base import GEOSGeometry

     8 from django.contrib.gis.geos.error import GEOSException, GEOSIndexError

     9 from django.contrib.gis.geos.geometries import Point, LineString, LinearRing, Polygon

    10 from django.contrib.gis.geos.libgeos import get_pointer_arr, GEOM_PTR

    11 from django.contrib.gis.geos.prototypes import create_collection, destroy_geom, geom_clone, geos_typeid, get_cs, get_geomn

    12 

    13 class GeometryCollection(GEOSGeometry):

    14     _allowed = (Point, LineString, LinearRing, Polygon)

    15     _typeid = 7

    16 

    17     def __init__(self, *args, **kwargs):

    18         "Initializes a Geometry Collection from a sequence of Geometry objects."

    19 

    20         # Checking the arguments

    21         if not args:

    22             raise TypeError, 'Must provide at least one Geometry to initialize %s.' % self.__class__.__name__

    23 

    24         if len(args) == 1: 

    25             # If only one geometry provided or a list of geometries is provided

    26             #  in the first argument.

    27             if isinstance(args[0], (TupleType, ListType)):

    28                 init_geoms = args[0]

    29             else:

    30                 init_geoms = args

    31         else:

    32             init_geoms = args

    33 

    34         # Ensuring that only the permitted geometries are allowed in this collection

    35         if False in [isinstance(geom, self._allowed) for geom in init_geoms]:

    36             raise TypeError('Invalid Geometry type encountered in the arguments.')

    37 

    38         # Creating the geometry pointer array.

    39         ngeoms = len(init_geoms)

    40         geoms = get_pointer_arr(ngeoms)

    41         for i in xrange(ngeoms): geoms[i] = geom_clone(init_geoms[i].ptr)

    42         super(GeometryCollection, self).__init__(create_collection(c_int(self._typeid), byref(geoms), c_uint(ngeoms)), **kwargs)

    43 

    44     def __getitem__(self, index):

    45         "Returns the Geometry from this Collection at the given index (0-based)."

    46         # Checking the index and returning the corresponding GEOS geometry.

    47         self._checkindex(index)

    48         return GEOSGeometry(geom_clone(get_geomn(self.ptr, index)), srid=self.srid)

    49 

    50     def __setitem__(self, index, geom):

    51         "Sets the Geometry at the specified index."

    52         self._checkindex(index)

    53         if not isinstance(geom, self._allowed):

    54             raise TypeError('Incompatible Geometry for collection.')

    55         

    56         ngeoms = len(self)

    57         geoms = get_pointer_arr(ngeoms)

    58         for i in xrange(ngeoms):

    59             if i == index:

    60                 geoms[i] = geom_clone(geom.ptr)

    61             else:

    62                 geoms[i] = geom_clone(get_geomn(self.ptr, i))

    63         

    64         # Creating a new collection, and destroying the contents of the previous poiner.

    65         prev_ptr = self.ptr

    66         srid = self.srid

    67         self._ptr = create_collection(c_int(self._typeid), byref(geoms), c_uint(ngeoms))

    68         if srid: self.srid = srid

    69         destroy_geom(prev_ptr)

    70 

    71     def __iter__(self):

    72         "Iterates over each Geometry in the Collection."

    73         for i in xrange(len(self)):

    74             yield self.__getitem__(i)

    75 

    76     def __len__(self):

    77         "Returns the number of geometries in this Collection."

    78         return self.num_geom

    79 

    80     def _checkindex(self, index):

    81         "Checks the given geometry index."

    82         if index < 0 or index >= self.num_geom:

    83             raise GEOSIndexError('invalid GEOS Geometry index: %s' % str(index))

    84 

    85     @property

    86     def kml(self):

    87         "Returns the KML for this Geometry Collection."

    88         return '<MultiGeometry>%s</MultiGeometry>' % ''.join([g.kml for g in self])

    89 

    90     @property

    91     def tuple(self):

    92         "Returns a tuple of all the coordinates in this Geometry Collection"

    93         return tuple([g.tuple for g in self])

    94     coords = tuple

    95 

    96 # MultiPoint, MultiLineString, and MultiPolygon class definitions.

    97 class MultiPoint(GeometryCollection): 

    98     _allowed = Point

    99     _typeid = 4

   100 class MultiLineString(GeometryCollection): 

   101     _allowed = (LineString, LinearRing)

   102     _typeid = 5

   103 class MultiPolygon(GeometryCollection): 

   104     _allowed = Polygon

   105     _typeid = 6