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"""
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 c_double, c_uint, byref
from types import ListType, TupleType
from django.contrib.gis.geos.error import GEOSException, GEOSIndexError
from django.contrib.gis.geos.libgeos import CS_PTR, HAS_NUMPY
from django.contrib.gis.geos.prototypes import cs_clone, cs_getdims, cs_getordinate, cs_getsize, cs_setordinate
if HAS_NUMPY: from numpy import ndarray
class GEOSCoordSeq(object):
"The internal representation of a list of coordinates inside a Geometry."
#### Python 'magic' routines ####
def __init__(self, ptr, z=False):
"Initializes 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):
"Iterates over each point in the coordinate sequence."
for i in xrange(self.size):
yield self[i]
def __len__(self):
"Returns the number of points in the coordinate sequence."
return int(self.size)
def __str__(self):
"Returns the string representation of the coordinate sequence."
return str(self.tuple)
def __getitem__(self, index):
"Returns the coordinate sequence value at the given index."
coords = [self.getX(index), self.getY(index)]
if self.dims == 3 and self._z:
coords.append(self.getZ(index))
return tuple(coords)
def __setitem__(self, index, value):
"Sets the coordinate sequence value at the given index."
# Checking the input value
if isinstance(value, (ListType, TupleType)):
pass
elif HAS_NUMPY and isinstance(value, 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
set_3d = True
else:
n_args = 2
set_3d = False
if len(value) != n_args:
raise TypeError('Dimension of value does not match.')
# Setting the X, Y, Z
self.setX(index, value[0])
self.setY(index, value[1])
if set_3d: self.setZ(index, value[2])
#### Internal Routines ####
def _checkindex(self, index):
"Checks the given index."
sz = self.size
if (sz < 1) or (index < 0) or (index >= sz):
raise GEOSIndexError('invalid GEOS Geometry index: %s' % str(index))
def _checkdim(self, dim):
"Checks the given dimension."
if dim < 0 or dim > 2:
raise GEOSException('invalid ordinate dimension "%d"' % dim)
@property
def ptr(self):
"""
Property for controlling access to coordinate sequence pointer,
preventing attempted access to a NULL memory location.
"""
if self._ptr: return self._ptr
else: raise GEOSException('NULL coordinate sequence pointer encountered.')
#### Ordinate getting and setting routines ####
def getOrdinate(self, dimension, index):
"Returns the value for the given dimension and index."
self._checkindex(index)
self._checkdim(dimension)
return cs_getordinate(self.ptr, index, dimension, byref(c_double()))
def setOrdinate(self, dimension, index, value):
"Sets the value for the given dimension and index."
self._checkindex(index)
self._checkdim(dimension)
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):
"Returns the size of this coordinate sequence."
return cs_getsize(self.ptr, byref(c_uint()))
@property
def dims(self):
"Returns the dimensions of this coordinate sequence."
return cs_getdims(self.ptr, byref(c_uint()))
@property
def hasz(self):
"""
Returns whether this coordinate sequence is 3D. This property value is
inherited from the parent Geometry.
"""
return self._z
### Other Methods ###
def clone(self):
"Clones this coordinate sequence."
return GEOSCoordSeq(cs_clone(self.ptr), self.hasz)
@property
def kml(self):
"Returns 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 xrange(len(self))]).strip()
@property
def tuple(self):
"Returns a tuple version of this coordinate sequence."
n = self.size
if n == 1: return self[0]
else: return tuple([self[i] for i in xrange(n)])
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