| """ |
| 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 |