django/contrib/gis/geos/coordseq.py
"""
This module houses the GEOSCoordSeq object, which is used internally
by GEOSGeometry to house the actual coordinates of the Point,
LineString, and LinearRing geometries.
"""
from ctypes import byref, c_byte, c_double, c_uint
from django.contrib.gis.geos import prototypes as capi
from django.contrib.gis.geos.base import GEOSBase
from django.contrib.gis.geos.error import GEOSException
from django.contrib.gis.geos.libgeos import CS_PTR
from django.contrib.gis.shortcuts import numpy
class GEOSCoordSeq(GEOSBase):
"The internal representation of a list of coordinates inside a Geometry."
ptr_type = CS_PTR
def __init__(self, ptr, z=False):
"Initialize from a GEOS pointer."
if not isinstance(ptr, CS_PTR):
raise TypeError("Coordinate sequence should initialize with a CS_PTR.")
self._ptr = ptr
self._z = z
def __iter__(self):
"Iterate over each point in the coordinate sequence."
for i in range(self.size):
yield self[i]
def __len__(self):
"Return the number of points in the coordinate sequence."
return self.size
def __str__(self):
"Return the string representation of the coordinate sequence."
return str(self.tuple)
def __getitem__(self, index):
"Return the coordinate sequence value at the given index."
self._checkindex(index)
return self._point_getter(index)
def __setitem__(self, index, value):
"Set the coordinate sequence value at the given index."
# Checking the input value
if isinstance(value, (list, tuple)):
pass
elif numpy and isinstance(value, numpy.ndarray):
pass
else:
raise TypeError(
"Must set coordinate with a sequence (list, tuple, or numpy array)."
)
# Checking the dims of the input
if self.dims == 3 and self._z:
n_args = 3
point_setter = self._set_point_3d
else:
n_args = 2
point_setter = self._set_point_2d
if len(value) != n_args:
raise TypeError("Dimension of value does not match.")
self._checkindex(index)
point_setter(index, value)
# #### Internal Routines ####
def _checkindex(self, index):
"Check the given index."
if not (0 <= index < self.size):
raise IndexError("invalid GEOS Geometry index: %s" % index)
def _checkdim(self, dim):
"Check the given dimension."
if dim < 0 or dim > 2:
raise GEOSException('invalid ordinate dimension "%d"' % dim)
def _get_x(self, index):
return capi.cs_getx(self.ptr, index, byref(c_double()))
def _get_y(self, index):
return capi.cs_gety(self.ptr, index, byref(c_double()))
def _get_z(self, index):
return capi.cs_getz(self.ptr, index, byref(c_double()))
def _set_x(self, index, value):
capi.cs_setx(self.ptr, index, value)
def _set_y(self, index, value):
capi.cs_sety(self.ptr, index, value)
def _set_z(self, index, value):
capi.cs_setz(self.ptr, index, value)
@property
def _point_getter(self):
return self._get_point_3d if self.dims == 3 and self._z else self._get_point_2d
def _get_point_2d(self, index):
return (self._get_x(index), self._get_y(index))
def _get_point_3d(self, index):
return (self._get_x(index), self._get_y(index), self._get_z(index))
def _set_point_2d(self, index, value):
x, y = value
self._set_x(index, x)
self._set_y(index, y)
def _set_point_3d(self, index, value):
x, y, z = value
self._set_x(index, x)
self._set_y(index, y)
self._set_z(index, z)
# #### Ordinate getting and setting routines ####
def getOrdinate(self, dimension, index):
"Return the value for the given dimension and index."
self._checkindex(index)
self._checkdim(dimension)
return capi.cs_getordinate(self.ptr, index, dimension, byref(c_double()))
def setOrdinate(self, dimension, index, value):
"Set the value for the given dimension and index."
self._checkindex(index)
self._checkdim(dimension)
capi.cs_setordinate(self.ptr, index, dimension, value)
def getX(self, index):
"Get the X value at the index."
return self.getOrdinate(0, index)
def setX(self, index, value):
"Set X with the value at the given index."
self.setOrdinate(0, index, value)
def getY(self, index):
"Get the Y value at the given index."
return self.getOrdinate(1, index)
def setY(self, index, value):
"Set Y with the value at the given index."
self.setOrdinate(1, index, value)
def getZ(self, index):
"Get Z with the value at the given index."
return self.getOrdinate(2, index)
def setZ(self, index, value):
"Set Z with the value at the given index."
self.setOrdinate(2, index, value)
# ### Dimensions ###
@property
def size(self):
"Return the size of this coordinate sequence."
return capi.cs_getsize(self.ptr, byref(c_uint()))
@property
def dims(self):
"Return the dimensions of this coordinate sequence."
return capi.cs_getdims(self.ptr, byref(c_uint()))
@property
def hasz(self):
"""
Return whether this coordinate sequence is 3D. This property value is
inherited from the parent Geometry.
"""
return self._z
# ### Other Methods ###
def clone(self):
"Clone this coordinate sequence."
return GEOSCoordSeq(capi.cs_clone(self.ptr), self.hasz)
@property
def kml(self):
"Return the KML representation for the coordinates."
# Getting the substitution string depending on whether the coordinates have
# a Z dimension.
if self.hasz:
substr = "%s,%s,%s "
else:
substr = "%s,%s,0 "
return (
"<coordinates>%s</coordinates>"
% "".join(substr % self[i] for i in range(len(self))).strip()
)
@property
def tuple(self):
"Return a tuple version of this coordinate sequence."
n = self.size
get_point = self._point_getter
if n == 1:
return get_point(0)
return tuple(get_point(i) for i in range(n))
@property
def is_counterclockwise(self):
"""Return whether this coordinate sequence is counterclockwise."""
ret = c_byte()
if not capi.cs_is_ccw(self.ptr, byref(ret)):
raise GEOSException(
'Error encountered in GEOS C function "%s".' % capi.cs_is_ccw.func_name
)
return ret.value == 1