131 lines
4.5 KiB
Python
131 lines
4.5 KiB
Python
"""
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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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import json
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from ctypes import byref, c_int, c_uint
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from django.contrib.gis.geos import prototypes as capi
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from django.contrib.gis.geos.error import GEOSException
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from django.contrib.gis.geos.geometry import GEOSGeometry, LinearGeometryMixin
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from django.contrib.gis.geos.libgeos import geos_version_info, get_pointer_arr
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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), iter(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 = get_pointer_arr(length)
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for i, g in enumerate(items):
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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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geoms[i] = capi.geom_clone(getattr(g, 'ptr', g))
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return capi.create_collection(c_int(self._typeid), byref(geoms), c_uint(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(capi.geom_clone(self._get_single_internal(index)), srid=self.srid)
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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 json(self):
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if self.__class__.__name__ == 'GeometryCollection':
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return json.dumps({
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'type': self.__class__.__name__,
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'geometries': [
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{'type': geom.__class__.__name__, 'coordinates': geom.coords}
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for geom in self
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],
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})
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return super().json
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geojson = json
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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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@property
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def closed(self):
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if geos_version_info()['version'] < '3.5':
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raise GEOSException("MultiLineString.closed requires GEOS >= 3.5.0.")
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return super().closed
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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 = (Point, LineString, LinearRing, Polygon, MultiPoint, MultiLineString, MultiPolygon)
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