Fixed #14318 -- Added `GEOSGeometry.valid_reason` property. Thanks, Rob Coup.

        "This property tests the validity of this Geometry."

        return capi.geos_isvalid(self.ptr)

    @property

    def valid_reason(self):

        """

        Returns a string containing the reason for any invalidity.

        """

        if not GEOS_PREPARE:

            raise GEOSException('Upgrade GEOS to 3.1 to get validity reason.')

        return capi.geos_isvalidreason(self.ptr)

    #### Binary predicates. ####

    def contains(self, other):

        "Returns true if other.within(this) returns true."

    to_hex, to_wkb, to_wkt

# Miscellaneous routines.

from django.contrib.gis.geos.prototypes.misc import geos_area, geos_distance, geos_length

from django.contrib.gis.geos.prototypes.misc import *

# Predicates

from django.contrib.gis.geos.prototypes.predicates import geos_hasz, geos_isempty, \

 ones that return the area, distance, and length.

"""

from ctypes import c_int, c_double, POINTER

from django.contrib.gis.geos.libgeos import GEOM_PTR

from django.contrib.gis.geos.prototypes.errcheck import check_dbl

from django.contrib.gis.geos.libgeos import GEOM_PTR, GEOS_PREPARE

from django.contrib.gis.geos.prototypes.errcheck import check_dbl, check_string

from django.contrib.gis.geos.prototypes.geom import geos_char_p

from django.contrib.gis.geos.prototypes.threadsafe import GEOSFunc

__all__ = ['geos_area', 'geos_distance', 'geos_length']

### ctypes generator function ###

def dbl_from_geom(func, num_geom=1):

    """

geos_area = dbl_from_geom(GEOSFunc('GEOSArea'))

geos_distance = dbl_from_geom(GEOSFunc('GEOSDistance'), num_geom=2)

geos_length = dbl_from_geom(GEOSFunc('GEOSLength'))

# Validity reason; only in GEOS 3.1+

if GEOS_PREPARE:

    geos_isvalidreason = GEOSFunc('GEOSisValidReason')

    geos_isvalidreason.argtypes = [GEOM_PTR]

    geos_isvalidreason.restype = geos_char_p

    geos_isvalidreason.errcheck = check_string

    __all__.append('geos_isvalidreason')

import ctypes, random, unittest, sys

from django.contrib.gis.geos import *

from django.contrib.gis.geos.base import gdal, numpy, GEOSBase

from django.contrib.gis.geos.libgeos import GEOS_PREPARE

from django.contrib.gis.geometry.test_data import TestDataMixin

class GEOSTest(unittest.TestCase, TestDataMixin):

        for geom, merged in zip(ref_geoms, ref_merged):

            self.assertEqual(merged, geom.merged)

    def test27_valid_reason(self):

        "Testing IsValidReason support"

        # Skipping tests if GEOS < v3.1.

        if not GEOS_PREPARE: return

        g = GEOSGeometry("POINT(0 0)")

        self.assert_(g.valid)

        self.assert_(isinstance(g.valid_reason, basestring))

        self.assertEqual(g.valid_reason, "Valid Geometry")

        print "\nBEGIN - expecting GEOS_NOTICE; safe to ignore.\n"

        g = GEOSGeometry("LINESTRING(0 0, 0 0)")

        self.assert_(not g.valid)

        self.assert_(isinstance(g.valid_reason, basestring))

        self.assertEqual(g.valid_reason, "Too few points in geometry component[0 0]")

        print "\nEND - expecting GEOS_NOTICE; safe to ignore.\n"

def suite():

    s = unittest.TestSuite()

    s.addTest(unittest.makeSuite(GEOSTest))

Returns a boolean indicating whether the geometry is valid.

.. attribute:: GEOSGeometry.valid_reason 

.. versionadded:: 1.3 

Returns a string describing the reason why a geometry is invalid. 

.. attribute:: GEOSGeometry.srid

Property that may be used to retrieve or set the SRID associated with the