[postgis-users] Cross sectional slice of 3d features

[David Bitner]

Does anyone know how best to go about creating some functions to work with
creating a cross-sectional slice of a 3d feature set.  I have a set of 3d
lines that I would like to draw an intersecting line over.  Using
Intersection() I can get the geometry of the points where the lines
intersect. What I would like is a result geometry with the Y-coord as the
elevation of the points of intersection and the X-coord as the distance
along the line where the intersection was (to make a penetration diagram).
I would also like to be able to get the average z value of the intersection
set.  As always, any help is greatly appreciated.

David