• 1.10
  • dev
  • Documentation version: 1.9

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, ProjectInterpolateMixin,
from django.contrib.gis.geos.point import Point
from django.contrib.gis.shortcuts import numpy
from django.utils.six.moves import range

[docs]class LineString(ProjectInterpolateMixin, GEOSGeometry): _init_func = capi.create_linestring _minlength = 2 has_cs = True def __init__(self, *args, **kwargs): """ Initializes 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 isinstance(coords, (tuple, list)): # Getting the number of coords and the number of dimensions -- which # must stay the same, e.g., no LineString((1, 2), (1, 2, 3)). ncoords = len(coords) if coords: ndim = len(coords[0]) else: raise TypeError('Cannot initialize on empty sequence.') self._checkdim(ndim) # Incrementing through each of the coordinates and verifying for i in range(1, ncoords): if not isinstance(coords[i], (tuple, list, Point)): raise TypeError('each coordinate should be a sequence (list or tuple)') if len(coords[i]) != ndim: raise TypeError('Dimension mismatch.') numpy_coords = False elif numpy and isinstance(coords, numpy.ndarray): shape = coords.shape # Using numpy's shape. if len(shape) != 2: raise TypeError('Too many dimensions.') self._checkdim(shape[1]) ncoords = shape[0] ndim = shape[1] numpy_coords = True else: raise TypeError('Invalid initialization input for LineStrings.') # Creating a coordinate sequence object because it is easier to # set the points using GEOSCoordSeq.__setitem__(). cs = GEOSCoordSeq(capi.create_cs(ncoords, ndim), z=bool(ndim == 3)) for i in range(ncoords): if numpy_coords: cs[i] = coords[i, :] elif isinstance(coords[i], Point): cs[i] = coords[i].tuple else: cs[i] = coords[i] # If SRID was passed in with the keyword arguments srid = kwargs.get('srid') # Calling the base geometry initialization with the returned pointer # from the function. super(LineString, self).__init__(self._init_func(cs.ptr), srid=srid) def __iter__(self): "Allows iteration over this LineString." for i in range(len(self)): yield self[i] def __len__(self): "Returns 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 # 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 self._post_init(self.srid) else: # can this happen? raise GEOSException('Geometry resulting from slice deletion was invalid.') def _set_single(self, index, value): self._checkindex(index) self._cs[index] = value def _checkdim(self, dim): if dim not in (2, 3): raise TypeError('Dimension mismatch.') # #### Sequence Properties #### @property def tuple(self): "Returns a tuple version of the geometry from the coordinate sequence." return self._cs.tuple coords = tuple def _listarr(self, func): """ Internal routine that returns a sequence (list) corresponding with the given function. Will 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): "Returns a numpy array for the LineString." return self._listarr(self._cs.__getitem__) @property def merged(self): "Returns the line merge of this LineString." return self._topology(capi.geos_linemerge(self.ptr)) @property def x(self): "Returns a list or numpy array of the X variable." return self._listarr(self._cs.getX) @property def y(self): "Returns a list or numpy array of the Y variable." return self._listarr(self._cs.getY) @property def z(self): "Returns 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
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