import sys
import numpy
__version__ = "0.1"
# need some python C API functions for strings.
cdef extern from "Python.h":
object PyString_FromString(char *)
# taken from numpy.pxi in numpy 1.0rc2.
cdef extern from "numpy/arrayobject.h":
ctypedef int npy_intp
ctypedef extern class numpy.ndarray [object PyArrayObject]:
cdef char *data
cdef int nd
cdef npy_intp *dimensions
cdef npy_intp *strides
cdef object base
# cdef dtype descr
cdef int flags
npy_intp PyArray_SIZE(ndarray arr)
npy_intp PyArray_ISCONTIGUOUS(ndarray arr)
void import_array()
# Initialize numpy
import_array()
# GENERAL NOTES:
#
# - Remember to call initGEOS() before any use of this library's
# functions, and call finishGEOS() when done.
#
# - Currently you have to explicitly GEOSGeom_destroy() all
# GEOSGeom objects to avoid memory leaks, and to free()
# all returned char * (unless const). This might change
# before first release to ensure greater API stability.
cdef extern from "geos_c.h":
# Supported geometry type IDs
cdef enum:
GEOS_POINT
GEOS_LINESTRING
GEOS_LINEARRING
GEOS_POLYGON
GEOS_MULTIPOINT
GEOS_MULTILINESTRING
GEOS_MULTIPOLYGON
GEOS_GEOMETRYCOLLECTION
ctypedef struct GEOSGeom:
pass
ctypedef struct GEOSCoordSeq:
pass
ctypedef void (*GEOSMessageHandler)(char *fmt, char *list)
char *GEOSversion()
void initGEOS(GEOSMessageHandler notice_function, GEOSMessageHandler error_function)
void finishGEOS()
GEOSCoordSeq *GEOSCoordSeq_create(unsigned int size, unsigned int dims)
void GEOSCoordSeq_destroy(GEOSCoordSeq* s)
int GEOSCoordSeq_setX(GEOSCoordSeq* s,unsigned int idx, double val)
int GEOSCoordSeq_setY(GEOSCoordSeq* s,unsigned int idx, double val)
int GEOSCoordSeq_getX(GEOSCoordSeq* s, unsigned int idx, double *val)
int GEOSCoordSeq_getY(GEOSCoordSeq* s, unsigned int idx, double *val)
GEOSGeom *GEOSGeom_createPoint(GEOSCoordSeq* s)
GEOSGeom *GEOSGeom_createLineString(GEOSCoordSeq* s)
GEOSGeom *GEOSGeom_createPolygon(GEOSGeom* shell, GEOSGeom** holes, unsigned int nholes)
GEOSGeom *GEOSGeom_createLinearRing(GEOSCoordSeq* s)
void GEOSGeom_destroy(GEOSGeom* g)
# Topology operations - return NULL on exception.
GEOSGeom *GEOSIntersection(GEOSGeom* g1, GEOSGeom* g2)
# Binary/Unary predicate - return 2 on exception, 1 on true, 0 on false
char GEOSIntersects(GEOSGeom* g1, GEOSGeom* g2)
char GEOSWithin(GEOSGeom* g1, GEOSGeom* g2)
char GEOSContains(GEOSGeom* g1, GEOSGeom* g2)
char GEOSisEmpty(GEOSGeom* g1)
char GEOSisValid(GEOSGeom* g1)
char GEOSisSimple(GEOSGeom* g1)
char GEOSisRing(GEOSGeom* g1)
# Geometry info
char *GEOSGeomType(GEOSGeom* g1)
int GEOSGeomTypeId(GEOSGeom* g1)
# Functions: Return 0 on exception, 1 otherwise
int GEOSArea(GEOSGeom* g1, double *area)
int GEOSLength(GEOSGeom* g1, double *length)
# returns -1 on error and 1 for non-multi geoms
int GEOSGetNumGeometries(GEOSGeom* g1)
# Return NULL on exception, Geometry must be a Collection.
# Returned object is a pointer to internal storage:
# it must NOT be destroyed directly.
GEOSGeom *GEOSGetGeometryN(GEOSGeom* g, int n)
int GEOSGetNumInteriorRings(GEOSGeom* g1)
# Return NULL on exception, Geometry must be a Polygon.
# Returned object is a pointer to internal storage:
# it must NOT be destroyed directly.
GEOSGeom *GEOSGetExteriorRing(GEOSGeom* g)
# Return NULL on exception.
# Geometry must be a LineString, LinearRing or Point.
GEOSCoordSeq *GEOSGeom_getCoordSeq(GEOSGeom* g)
int GEOSCoordSeq_getSize(GEOSCoordSeq *s, unsigned int *size)
cdef void notice_h(char *fmt, char*msg):
format = PyString_FromString(fmt)
message = PyString_FromString(msg)
try:
warn_msg = format % message
except:
warn_msg = format
sys.stdout.write('GEOS_NOTICE: %s\n' % warn_msg)
cdef void error_h(char *fmt, char*msg):
format = PyString_FromString(fmt)
message = PyString_FromString(msg)
try:
warn_msg = format % message
except:
warn_msg = format
sys.stderr.write('GEOS_ERROR: %s\n' % warn_msg)
# check library version
cdef geos_version():
return PyString_FromString(GEOSversion())
__geos_version__ = geos_version() # module variable.
if __geos_version__ != "2.2.3-CAPI-1.1.1":
raise ValueError('version 2.2.3 of the geos library is required')
# intialize GEOS (parameters are notice and error function callbacks).
initGEOS(notice_h, error_h)
cdef class BaseGeometry:
cdef GEOSGeom *_geom
cdef unsigned int _npts
cdef public object boundary
def is_valid(self):
cdef char valid
valid = GEOSisValid(self._geom)
if valid:
return True
else:
return False
def geom_type(self):
return PyString_FromString(GEOSGeomType(self._geom))
def within(self, BaseGeometry geom):
cdef GEOSGeom *g1, *g2
cdef char answer
g1 = self._geom
g2 = geom._geom
answer = GEOSWithin(g1, g2)
if answer:
return True
else:
return False
def intersects(self, BaseGeometry geom):
cdef GEOSGeom *g1, *g2
cdef char answer
g1 = self._geom
g2 = geom._geom
answer = GEOSIntersects(g1, g2)
if answer:
return True
else:
return False
def intersection(self, BaseGeometry geom):
cdef GEOSGeom *g1, *g2, *g3, *gout
cdef char answer
cdef int numgeoms, i, typeid
g1 = self._geom
g2 = geom._geom
g3 = GEOSIntersection(g1, g2)
typeid = GEOSGeomTypeId(g3)
if typeid == GEOS_POLYGON:
b = _get_coords(g3)
p = Polygon(b)
pout = [p]
elif typeid == GEOS_LINESTRING:
b = _get_coords(g3)
p = LineString(b)
pout = [p]
elif typeid == GEOS_MULTIPOLYGON:
numgeoms = GEOSGetNumGeometries(g3)
pout = []
for i from 0 <= i < numgeoms:
gout = GEOSGetGeometryN(g3, i)
b = _get_coords(gout)
p = Polygon(b)
pout.append(p)
elif typeid == GEOS_MULTILINESTRING:
numgeoms = GEOSGetNumGeometries(g3)
pout = []
for i from 0 <= i < numgeoms:
gout = GEOSGetGeometryN(g3, i)
b = _get_coords(gout)
p = LineString(b)
pout.append(p)
else:
type = PyString_FromString(GEOSGeomType(g3))
raise NotImplementedError("intersections of type '%s' not yet implemented" % (type))
GEOSGeom_destroy(g3)
return pout
def get_coords(self):
return _get_coords(self._geom)
def __dealloc__(self):
"""destroy GEOS geometry"""
GEOSGeom_destroy(self._geom)
def __reduce__(self):
"""special method that allows geos instance to be pickled"""
return (self.__class__,(self.boundary,))
cdef class Polygon(BaseGeometry):
def __init__(self, ndarray b):
cdef unsigned int M, m, i
cdef double dx, dy
cdef double *bbuffer
cdef GEOSCoordSeq *cs
cdef GEOSGeom *lr
# make sure data is contiguous.
# if not, make a local copy.
if not PyArray_ISCONTIGUOUS(b):
b = b.copy()
m = b.shape[0]
# Add closing coordinates to sequence?
if b[-1,0] != b[0,0] or b[-1,1] != b[0,1]:
M = m + 1
else:
M = m
self._npts = M
# Create a coordinate sequence
cs = GEOSCoordSeq_create(M, 2)
# add to coordinate sequence
bbuffer = <double *>b.data
for i from 0 <= i < m:
dx = bbuffer[2*i]
dy = bbuffer[2*i+1]
# Because of a bug in the GEOS C API,
# always set X before Y
GEOSCoordSeq_setX(cs, i, dx)
GEOSCoordSeq_setY(cs, i, dy)
# Add closing coordinates to sequence?
if M > m:
dx = bbuffer[0]
dy = bbuffer[1]
GEOSCoordSeq_setX(cs, M-1, dx)
GEOSCoordSeq_setY(cs, M-1, dy)
# create LinearRing
lr = GEOSGeom_createLinearRing(cs)
# create Polygon from LinearRing (assuming no holes)
self._geom = GEOSGeom_createPolygon(lr,NULL,0)
self.boundary = b
def area(self):
cdef double area
GEOSArea(self._geom, &area)
return area
cdef class LineString(BaseGeometry):
def __init__(self, ndarray b):
cdef double dx, dy
cdef GEOSCoordSeq *cs
cdef int i, M
cdef double *bbuffer
# make sure data is contiguous.
# if not, make a local copy.
if not PyArray_ISCONTIGUOUS(b):
b = b.copy()
M = b.shape[0]
self._npts = M
# Create a coordinate sequence
cs = GEOSCoordSeq_create(M, 2)
# add to coordinate sequence
bbuffer = <double *>b.data
for i from 0 <= i < M:
dx = bbuffer[2*i]
dy = bbuffer[2*i+1]
# Because of a bug in the GEOS C API,
# always set X before Y
GEOSCoordSeq_setX(cs, i, dx)
GEOSCoordSeq_setY(cs, i, dy)
# create LineString
self._geom = GEOSGeom_createLineString(cs)
self.boundary = b
cdef class Point(BaseGeometry):
cdef public x,y
def __init__(self, b):
cdef double dx, dy
cdef GEOSCoordSeq *cs
# Create a coordinate sequence
cs = GEOSCoordSeq_create(1, 2)
dx = b[0]; dy = b[1]
GEOSCoordSeq_setX(cs, 0, dx)
GEOSCoordSeq_setY(cs, 0, dy)
self._geom = GEOSGeom_createPoint(cs)
self._npts = 1
self.boundary = b
cdef _get_coords(GEOSGeom *geom):
cdef GEOSCoordSeq *cs
cdef GEOSGeom *lr
cdef unsigned int i, M
cdef double dx, dy
cdef ndarray b
cdef double *bbuffer
if GEOSGeomTypeId(geom) == GEOS_POLYGON:
lr = GEOSGetExteriorRing(geom)
cs = GEOSGeom_getCoordSeq(lr)
else:
cs = GEOSGeom_getCoordSeq(geom)
GEOSCoordSeq_getSize(cs, &M)
b = numpy.empty((M,2), numpy.float64)
bbuffer = <double *>b.data
for i from 0 <= i < M:
GEOSCoordSeq_getX(cs, i, &dx)
GEOSCoordSeq_getY(cs, i, &dy)
bbuffer[2*i] = dx
bbuffer[2*i+1] = dy
return b
