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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
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.
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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