"""
This module houses the Point, LineString, LinearRing, and Polygon OGC
geometry classes. All geometry classes in this module inherit from
GEOSGeometry.
"""
from ctypes import c_uint, byref
from django.contrib.gis.geos.base import GEOSGeometry
from django.contrib.gis.geos.coordseq import GEOSCoordSeq
from django.contrib.gis.geos.error import GEOSException, GEOSIndexError
from django.contrib.gis.geos.libgeos import get_pointer_arr, GEOM_PTR, HAS_NUMPY
from django.contrib.gis.geos.prototypes import *
if HAS_NUMPY: from numpy import ndarray, array
class Point(GEOSGeometry):
def __init__(self, x, y=None, z=None, srid=None):
"""
The Point object may be initialized with either a tuple, or individual
parameters.
For Example:
>>> p = Point((5, 23)) # 2D point, passed in as a tuple
>>> p = Point(5, 23, 8) # 3D point, passed in with individual parameters
"""
if isinstance(x, (tuple, list)):
# Here a tuple or list was passed in under the `x` parameter.
ndim = len(x)
if ndim < 2 or ndim > 3:
raise TypeError('Invalid sequence parameter: %s' % str(x))
coords = x
elif isinstance(x, (int, float, long)) and isinstance(y, (int, float, long)):
# Here X, Y, and (optionally) Z were passed in individually, as parameters.
if isinstance(z, (int, float, long)):
ndim = 3
coords = [x, y, z]
else:
ndim = 2
coords = [x, y]
else:
raise TypeError('Invalid parameters given for Point initialization.')
# Creating the coordinate sequence, and setting X, Y, [Z]
cs = create_cs(c_uint(1), c_uint(ndim))
cs_setx(cs, 0, coords[0])
cs_sety(cs, 0, coords[1])
if ndim == 3: cs_setz(cs, 0, coords[2])
# Initializing using the address returned from the GEOS
# createPoint factory.
super(Point, self).__init__(create_point(cs), srid=srid)
def __len__(self):
"Returns the number of dimensions for this Point (either 0, 2 or 3)."
if self.empty: return 0
if self.hasz: return 3
else: return 2
def get_x(self):
"Returns the X component of the Point."
return self._cs.getOrdinate(0, 0)
def set_x(self, value):
"Sets the X component of the Point."
self._cs.setOrdinate(0, 0, value)
def get_y(self):
"Returns the Y component of the Point."
return self._cs.getOrdinate(1, 0)
def set_y(self, value):
"Sets the Y component of the Point."
self._cs.setOrdinate(1, 0, value)
def get_z(self):
"Returns the Z component of the Point."
if self.hasz:
return self._cs.getOrdinate(2, 0)
else:
return None
def set_z(self, value):
"Sets the Z component of the Point."
if self.hasz:
self._cs.setOrdinate(2, 0, value)
else:
raise GEOSException('Cannot set Z on 2D Point.')
# X, Y, Z properties
x = property(get_x, set_x)
y = property(get_y, set_y)
z = property(get_z, set_z)
### Tuple setting and retrieval routines. ###
def get_coords(self):
"Returns a tuple of the point."
return self._cs.tuple
def set_coords(self, tup):
"Sets the coordinates of the point with the given tuple."
self._cs[0] = tup
# The tuple and coords properties
tuple = property(get_coords, set_coords)
coords = tuple
class LineString(GEOSGeometry):
#### Python 'magic' routines ####
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 xrange(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 HAS_NUMPY and isinstance(coords, 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(create_cs(ncoords, ndim), z=bool(ndim==3))
for i in xrange(ncoords):
if numpy_coords: cs[i] = coords[i,:]
elif isinstance(coords[i], Point): cs[i] = coords[i].tuple
else: cs[i] = coords[i]
# Getting the correct initialization function
if kwargs.get('ring', False):
func = create_linearring
else:
func = create_linestring
# If SRID was passed in with the keyword arguments
srid = kwargs.get('srid', None)
# Calling the base geometry initialization with the returned pointer
# from the function.
super(LineString, self).__init__(func(cs.ptr), srid=srid)
def __getitem__(self, index):
"Gets the point at the specified index."
return self._cs[index]
def __setitem__(self, index, value):
"Sets the point at the specified index, e.g., line_str[0] = (1, 2)."
self._cs[index] = value
def __iter__(self):
"Allows iteration over this LineString."
for i in xrange(len(self)):
yield self[i]
def __len__(self):
"Returns the number of points in this LineString."
return len(self._cs)
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 xrange(len(self))]
if HAS_NUMPY: return 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 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.
class LinearRing(LineString):
def __init__(self, *args, **kwargs):
"Overriding the initialization function to set the ring keyword."
kwargs['ring'] = True # Setting the ring keyword argument to True
super(LinearRing, self).__init__(*args, **kwargs)
class Polygon(GEOSGeometry):
def __init__(self, *args, **kwargs):
"""
Initializes on an exterior ring and a sequence of holes (both
instances may be either LinearRing instances, or a tuple/list
that may be constructed into a LinearRing).
Examples of initialization, where shell, hole1, and hole2 are
valid LinearRing geometries:
>>> poly = Polygon(shell, hole1, hole2)
>>> poly = Polygon(shell, (hole1, hole2))
Example where a tuple parameters are used:
>>> poly = Polygon(((0, 0), (0, 10), (10, 10), (0, 10), (0, 0)),
((4, 4), (4, 6), (6, 6), (6, 4), (4, 4)))
"""
if not args:
raise TypeError('Must provide at list one LinearRing instance to initialize Polygon.')
# Getting the ext_ring and init_holes parameters from the argument list
ext_ring = args[0]
init_holes = args[1:]
n_holes = len(init_holes)
# If initialized as Polygon(shell, (LinearRing, LinearRing)) [for backward-compatibility]
if n_holes == 1 and isinstance(init_holes[0], (tuple, list)) and \
(len(init_holes[0]) == 0 or isinstance(init_holes[0][0], LinearRing)):
init_holes = init_holes[0]
n_holes = len(init_holes)
# Ensuring the exterior ring and holes parameters are LinearRing objects
# or may be instantiated into LinearRings.
ext_ring = self._construct_ring(ext_ring, 'Exterior parameter must be a LinearRing or an object that can initialize a LinearRing.')
holes_list = [] # Create new list, cause init_holes is a tuple.
for i in xrange(n_holes):
holes_list.append(self._construct_ring(init_holes[i], 'Holes parameter must be a sequence of LinearRings or objects that can initialize to LinearRings'))
# Why another loop? Because if a TypeError is raised, cloned pointers will
# be around that can't be cleaned up.
holes = get_pointer_arr(n_holes)
for i in xrange(n_holes): holes[i] = geom_clone(holes_list[i].ptr)
# Getting the shell pointer address.
shell = geom_clone(ext_ring.ptr)
# Calling with the GEOS createPolygon factory.
super(Polygon, self).__init__(create_polygon(shell, byref(holes), c_uint(n_holes)), **kwargs)
def __getitem__(self, index):
"""
Returns the ring at the specified index. The first index, 0, will
always return the exterior ring. Indices > 0 will return the
interior ring at the given index (e.g., poly[1] and poly[2] would
return the first and second interior ring, respectively).
"""
if index == 0:
return self.exterior_ring
else:
# Getting the interior ring, have to subtract 1 from the index.
return self.get_interior_ring(index-1)
def __setitem__(self, index, ring):
"Sets the ring at the specified index with the given ring."
# Checking the index and ring parameters.
self._checkindex(index)
if not isinstance(ring, LinearRing):
raise TypeError('must set Polygon index with a LinearRing object')
# Getting the shell
if index == 0:
shell = geom_clone(ring.ptr)
else:
shell = geom_clone(get_extring(self.ptr))
# Getting the interior rings (holes)
nholes = len(self)-1
if nholes > 0:
holes = get_pointer_arr(nholes)
for i in xrange(nholes):
if i == (index-1):
holes[i] = geom_clone(ring.ptr)
else:
holes[i] = geom_clone(get_intring(self.ptr, i))
holes_param = byref(holes)
else:
holes_param = None
# Getting the current pointer, replacing with the newly constructed
# geometry, and destroying the old geometry.
prev_ptr = self.ptr
srid = self.srid
self._ptr = create_polygon(shell, holes_param, c_uint(nholes))
if srid: self.srid = srid
destroy_geom(prev_ptr)
def __iter__(self):
"Iterates over each ring in the polygon."
for i in xrange(len(self)):
yield self[i]
def __len__(self):
"Returns the number of rings in this Polygon."
return self.num_interior_rings + 1
def _checkindex(self, index):
"Internal routine for checking the given ring index."
if index < 0 or index >= len(self):
raise GEOSIndexError('invalid Polygon ring index: %s' % index)
def _construct_ring(self, param, msg=''):
"Helper routine for trying to construct a ring from the given parameter."
if isinstance(param, LinearRing): return param
try:
ring = LinearRing(param)
return ring
except TypeError:
raise TypeError(msg)
def get_interior_ring(self, ring_i):
"""
Gets the interior ring at the specified index, 0 is for the first
interior ring, not the exterior ring.
"""
self._checkindex(ring_i+1)
return GEOSGeometry(geom_clone(get_intring(self.ptr, ring_i)), srid=self.srid)
#### Polygon Properties ####
@property
def num_interior_rings(self):
"Returns the number of interior rings."
# Getting the number of rings
return get_nrings(self.ptr)
def get_ext_ring(self):
"Gets the exterior ring of the Polygon."
return GEOSGeometry(geom_clone(get_extring(self.ptr)), srid=self.srid)
def set_ext_ring(self, ring):
"Sets the exterior ring of the Polygon."
self[0] = ring
# properties for the exterior ring/shell
exterior_ring = property(get_ext_ring, set_ext_ring)
shell = exterior_ring
@property
def tuple(self):
"Gets the tuple for each ring in this Polygon."
return tuple([self[i].tuple for i in xrange(len(self))])
coords = tuple
@property
def kml(self):
"Returns the KML representation of this Polygon."
inner_kml = ''.join(["<innerBoundaryIs>%s</innerBoundaryIs>" % self[i+1].kml
for i in xrange(self.num_interior_rings)])
return "<Polygon><outerBoundaryIs>%s</outerBoundaryIs>%s</Polygon>" % (self[0].kml, inner_kml)