Source code for django.contrib.gis.geos.linestring

from django.contrib.gis.geos import prototypes as capi
from django.contrib.gis.geos.coordseq import GEOSCoordSeq
from django.contrib.gis.geos.error import GEOSException
from django.contrib.gis.geos.geometry import GEOSGeometry, LinearGeometryMixin
from django.contrib.gis.geos.point import Point
from django.contrib.gis.shortcuts import numpy

[docs]class LineString(LinearGeometryMixin, GEOSGeometry): _init_func = capi.create_linestring _minlength = 2 has_cs = True def __init__(self, *args, **kwargs): """ Initialize on the given sequence -- may take lists, tuples, NumPy arrays of X,Y pairs, or Point objects. If Point objects are used, ownership is _not_ transferred to the LineString object. Examples: ls = LineString((1, 1), (2, 2)) ls = LineString([(1, 1), (2, 2)]) ls = LineString(array([(1, 1), (2, 2)])) ls = LineString(Point(1, 1), Point(2, 2)) """ # If only one argument provided, set the coords array appropriately if len(args) == 1: coords = args[0] else: coords = args if not (isinstance(coords, (tuple, list)) or numpy and isinstance(coords, numpy.ndarray)): raise TypeError('Invalid initialization input for LineStrings.') # If SRID was passed in with the keyword arguments srid = kwargs.get('srid') ncoords = len(coords) if not ncoords: super().__init__(self._init_func(None), srid=srid) return if ncoords < self._minlength: raise ValueError( '%s requires at least %d points, got %s.' % ( self.__class__.__name__, self._minlength, ncoords, ) ) numpy_coords = not isinstance(coords, (tuple, list)) if numpy_coords: shape = coords.shape # Using numpy's shape. if len(shape) != 2: raise TypeError('Too many dimensions.') self._checkdim(shape[1]) ndim = shape[1] else: # Getting the number of coords and the number of dimensions -- which # must stay the same, e.g., no LineString((1, 2), (1, 2, 3)). ndim = None # Incrementing through each of the coordinates and verifying for coord in coords: if not isinstance(coord, (tuple, list, Point)): raise TypeError('Each coordinate should be a sequence (list or tuple)') if ndim is None: ndim = len(coord) self._checkdim(ndim) elif len(coord) != ndim: raise TypeError('Dimension mismatch.') # Creating a coordinate sequence object because it is easier to # set the points using its methods. cs = GEOSCoordSeq(capi.create_cs(ncoords, ndim), z=bool(ndim == 3)) point_setter = cs._set_point_3d if ndim == 3 else cs._set_point_2d for i in range(ncoords): if numpy_coords: point_coords = coords[i, :] elif isinstance(coords[i], Point): point_coords = coords[i].tuple else: point_coords = coords[i] point_setter(i, point_coords) # Calling the base geometry initialization with the returned pointer # from the function. super().__init__(self._init_func(cs.ptr), srid=srid) def __iter__(self): "Allow iteration over this LineString." for i in range(len(self)): yield self[i] def __len__(self): "Return the number of points in this LineString." return len(self._cs) def _get_single_external(self, index): return self._cs[index] _get_single_internal = _get_single_external def _set_list(self, length, items): ndim = self._cs.dims hasz = self._cs.hasz # I don't understand why these are different srid = self.srid # create a new coordinate sequence and populate accordingly cs = GEOSCoordSeq(capi.create_cs(length, ndim), z=hasz) for i, c in enumerate(items): cs[i] = c ptr = self._init_func(cs.ptr) if ptr: capi.destroy_geom(self.ptr) self.ptr = ptr if srid is not None: self.srid = srid self._post_init() else: # can this happen? raise GEOSException('Geometry resulting from slice deletion was invalid.') def _set_single(self, index, value): self._cs[index] = value def _checkdim(self, dim): if dim not in (2, 3): raise TypeError('Dimension mismatch.') # #### Sequence Properties #### @property def tuple(self): "Return a tuple version of the geometry from the coordinate sequence." return self._cs.tuple coords = tuple def _listarr(self, func): """ Return a sequence (list) corresponding with the given function. Return a numpy array if possible. """ lst = [func(i) for i in range(len(self))] if numpy: return numpy.array(lst) # ARRRR! else: return lst @property def array(self): "Return a numpy array for the LineString." return self._listarr(self._cs.__getitem__) @property def x(self): "Return a list or numpy array of the X variable." return self._listarr(self._cs.getX) @property def y(self): "Return a list or numpy array of the Y variable." return self._listarr(self._cs.getY) @property def z(self): "Return a list or numpy array of the Z variable." if not self.hasz: return None else: return self._listarr(self._cs.getZ)
# LinearRings are LineStrings used within Polygons.
[docs]class LinearRing(LineString): _minlength = 4 _init_func = capi.create_linearring @property def is_counterclockwise(self): if self.empty: raise ValueError( 'Orientation of an empty LinearRing cannot be determined.' ) return self._cs.is_counterclockwise
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