Looking for triangulator/interpolator

[Grant Edwards]

I need to interpolate an irregularly spaced set of sampled
points: Given a set of x,y,z points, I need to interpolate z
values for a much finer x,y grid.

I tried using the scipy sandbox delaunay module, but the
interpolators don't work: the natural neighbor interpolator
produces a surface with "holes" in it: the interpolator returns
NaNs for no reason for certain regions within the convex hull
(the convex hull looks right, and the input Z values in that
region don't look any different that regions that work).  

The linear interpolator just segfualts no matter what data I
try with it.

In the past i've used the Delny/libqhull module, but it doesn't
do interpolation, so I had to write the interpolator in Python
(which works but is very slow).

Is there any "off the shelf" module that does interpolation of
irregularly spaced data?

-- 
Grant Edwards                   grante             Yow!  LOOK!! Sullen
                                  at               American teens wearing
                               visi.com            MADRAS shorts and "Flock of
                                                   Seagulls" HAIRCUTS!