```I've made some progress identifying the problem. It seems that all of
this is only related to matplotlib and not numpy.```
```
I attach a test case showing the problem.

Didrik
```
```'''
Pylab - numpy - Numeric - gdal interaction problem

In order to run this testcase you need to install the following Python modules
: python-gdal, python-matplotlib, python-Numeric and python-numpy

Author : Didrik Pinte <[EMAIL PROTECTED]>
Date   : 30 may 2006
'''
import unittest
import ogr

class TestIntersection(unittest.TestCase):

def test_polyintersection(self):
'''
Test that surface intersection between two polygons returns a polygon
'''

t1wkt = 'POLYGON ((-1.0 50.5, -0.5 51.2, 0.3 50.9, -1 50.5))'
t2wkt = 'POLYGON((-0.7 50.3, 0.1 51.0, 0.6 50.1, -0.7 50.3))'

t1 = ogr.CreateGeometryFromWkt(t1wkt)
t2 = ogr.CreateGeometryFromWkt(t2wkt)

int1  = t1.Intersection(t2)
self.assertEqual(int1.GetGeometryType(), ogr.wkbPolygon)

def test_polyintersection_pylab(self):
'''
Test that surface intersection between two polygons returns a polygon
'''

import pylab

t1wkt = 'POLYGON ((-1.0 50.5, -0.5 51.2, 0.3 50.9, -1 50.5))'
t2wkt = 'POLYGON((-0.7 50.3, 0.1 51.0, 0.6 50.1, -0.7 50.3))'

t1 = ogr.CreateGeometryFromWkt(t1wkt)
t2 = ogr.CreateGeometryFromWkt(t2wkt)

int1  = t1.Intersection(t2)
self.assertEqual(int1.GetGeometryType(), ogr.wkbPolygon)

del pylab

if __name__ == '__main__':
unittest.main()
```

signature.asc
```_______________________________________________