Vertically interpolated curves and cross sections - how to create?

[Tero Siili]

A question that has been bothering me for some time: is there a GrADS
script or function somewhere, which generates vertically interpolated
cross sections (or vertical profile curves) of a variable/quantity? I
know there are scripts to produce interpolations (apparently) to a
single altitude or pressure level, but if I am not mistaken, these
generate a horizontal cross section, i.e. the quantity at the wanted
level as a function of latitude and longitude (typically).

What I am looking for and need is for instance a cross-sectional
field displayed as a function of latitude/longitude and altitude (or
pressure) derived from data originally given in dimensionless (sigma
or eta) coordinates. If the underlying topography could be overlayed
on top of the field, even better. Similarly, it would be nice to have
a tool displaying a vertical profile of a given quantity
interpolated to given set of altitude or pressure levels (either some
absolute or above-the-surface set).

Does anybody out there have something like this written? Or perhaps a
tool that I could use as a starting point? All pointers are
appreciated (and I have tried to search the archive of this list, to
not much avail).

Tero Siili
--
Finnish Meteorological Institute
Space research
P.O. Box 503
FIN-00101 Helsinki, Finland
Tel.    +358 9 19294660          Telefax +358 9 19294603

"Science is like sex: sometimes something useful comes out,
    but that is not the reason we are doing it" -- (Richard Feynman)