121 lines
3.8 KiB
Python
121 lines
3.8 KiB
Python
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"""
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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 django.contrib.gis.geos import prototypes as capi
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from django.contrib.gis.geos.geometry import GEOSGeometry, LinearGeometryMixin
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from django.contrib.gis.geos.libgeos import GEOM_PTR
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from django.contrib.gis.geos.linestring import LinearRing, LineString
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from django.contrib.gis.geos.point import Point
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from django.contrib.gis.geos.polygon import Polygon
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class GeometryCollection(GEOSGeometry):
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_typeid = 7
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def __init__(self, *args, **kwargs):
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"Initialize a Geometry Collection from a sequence of Geometry objects."
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# Checking the arguments
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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], (tuple, list)):
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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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# this is moved to list mixin super class
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self._check_allowed(init_geoms)
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# Creating the geometry pointer array.
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collection = self._create_collection(len(init_geoms), init_geoms)
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super().__init__(collection, **kwargs)
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def __iter__(self):
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"Iterate over each Geometry in the Collection."
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for i in range(len(self)):
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yield self[i]
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def __len__(self):
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"Return the number of geometries in this Collection."
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return self.num_geom
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# ### Methods for compatibility with ListMixin ###
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def _create_collection(self, length, items):
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# Creating the geometry pointer array.
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geoms = (GEOM_PTR * length)(
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*[
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# this is a little sloppy, but makes life easier
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# allow GEOSGeometry types (python wrappers) or pointer types
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capi.geom_clone(getattr(g, "ptr", g))
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for g in items
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]
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)
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return capi.create_collection(self._typeid, geoms, length)
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def _get_single_internal(self, index):
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return capi.get_geomn(self.ptr, index)
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def _get_single_external(self, index):
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"Return 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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return GEOSGeometry(
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capi.geom_clone(self._get_single_internal(index)), srid=self.srid
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)
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def _set_list(self, length, items):
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"Create a new collection, and destroy the contents of the previous pointer."
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prev_ptr = self.ptr
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srid = self.srid
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self.ptr = self._create_collection(length, items)
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if srid:
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self.srid = srid
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capi.destroy_geom(prev_ptr)
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_set_single = GEOSGeometry._set_single_rebuild
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_assign_extended_slice = GEOSGeometry._assign_extended_slice_rebuild
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@property
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def kml(self):
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"Return 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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"Return 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(LinearGeometryMixin, 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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# Setting the allowed types here since GeometryCollection is defined before
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# its subclasses.
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GeometryCollection._allowed = (
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Point,
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LineString,
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LinearRing,
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Polygon,
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MultiPoint,
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MultiLineString,
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MultiPolygon,
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)
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