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105 lines
4.1 KiB
105 lines
4.1 KiB
""" |
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This module houses the Geometry Collection objects: |
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GeometryCollection, MultiPoint, MultiLineString, and MultiPolygon |
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""" |
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from ctypes import c_int, c_uint, byref |
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from types import TupleType, ListType |
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from django.contrib.gis.geos.base import GEOSGeometry |
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from django.contrib.gis.geos.error import GEOSException, GEOSIndexError |
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from django.contrib.gis.geos.geometries import Point, LineString, LinearRing, Polygon |
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from django.contrib.gis.geos.libgeos import get_pointer_arr, GEOM_PTR |
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from django.contrib.gis.geos.prototypes import create_collection, destroy_geom, geom_clone, geos_typeid, get_cs, get_geomn |
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|
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class GeometryCollection(GEOSGeometry): |
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_allowed = (Point, LineString, LinearRing, Polygon) |
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_typeid = 7 |
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def __init__(self, *args, **kwargs): |
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"Initializes a Geometry Collection from a sequence of Geometry objects." |
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|
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# Checking the arguments |
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if not args: |
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raise TypeError, 'Must provide at least one Geometry to initialize %s.' % self.__class__.__name__ |
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if len(args) == 1: |
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# If only one geometry provided or a list of geometries is provided |
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# in the first argument. |
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if isinstance(args[0], (TupleType, ListType)): |
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init_geoms = args[0] |
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else: |
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init_geoms = args |
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else: |
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init_geoms = args |
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# Ensuring that only the permitted geometries are allowed in this collection |
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if False in [isinstance(geom, self._allowed) for geom in init_geoms]: |
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raise TypeError('Invalid Geometry type encountered in the arguments.') |
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# Creating the geometry pointer array. |
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ngeoms = len(init_geoms) |
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geoms = get_pointer_arr(ngeoms) |
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for i in xrange(ngeoms): geoms[i] = geom_clone(init_geoms[i].ptr) |
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super(GeometryCollection, self).__init__(create_collection(c_int(self._typeid), byref(geoms), c_uint(ngeoms)), **kwargs) |
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def __getitem__(self, index): |
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"Returns the Geometry from this Collection at the given index (0-based)." |
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# Checking the index and returning the corresponding GEOS geometry. |
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self._checkindex(index) |
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return GEOSGeometry(geom_clone(get_geomn(self.ptr, index)), srid=self.srid) |
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def __setitem__(self, index, geom): |
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"Sets the Geometry at the specified index." |
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self._checkindex(index) |
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if not isinstance(geom, self._allowed): |
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raise TypeError('Incompatible Geometry for collection.') |
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ngeoms = len(self) |
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geoms = get_pointer_arr(ngeoms) |
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for i in xrange(ngeoms): |
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if i == index: |
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geoms[i] = geom_clone(geom.ptr) |
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else: |
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geoms[i] = geom_clone(get_geomn(self.ptr, i)) |
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# Creating a new collection, and destroying the contents of the previous poiner. |
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prev_ptr = self.ptr |
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srid = self.srid |
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self._ptr = create_collection(c_int(self._typeid), byref(geoms), c_uint(ngeoms)) |
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if srid: self.srid = srid |
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destroy_geom(prev_ptr) |
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def __iter__(self): |
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"Iterates over each Geometry in the Collection." |
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for i in xrange(len(self)): |
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yield self.__getitem__(i) |
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def __len__(self): |
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"Returns the number of geometries in this Collection." |
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return self.num_geom |
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def _checkindex(self, index): |
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"Checks the given geometry index." |
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if index < 0 or index >= self.num_geom: |
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raise GEOSIndexError('invalid GEOS Geometry index: %s' % str(index)) |
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@property |
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def kml(self): |
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"Returns the KML for this Geometry Collection." |
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return '<MultiGeometry>%s</MultiGeometry>' % ''.join([g.kml for g in self]) |
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@property |
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def tuple(self): |
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"Returns a tuple of all the coordinates in this Geometry Collection" |
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return tuple([g.tuple for g in self]) |
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coords = tuple |
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# MultiPoint, MultiLineString, and MultiPolygon class definitions. |
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class MultiPoint(GeometryCollection): |
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_allowed = Point |
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_typeid = 4 |
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class MultiLineString(GeometryCollection): |
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_allowed = (LineString, LinearRing) |
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_typeid = 5 |
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class MultiPolygon(GeometryCollection): |
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_allowed = Polygon |
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_typeid = 6
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