Plotting Cross Sections with Topo and Variables

[Morgan Silverman]

Hello,
I am hoping someone can help me with this. I am trying to plot cross
sections of my data and am having problems. I want to plot a cross section
over that shows the topography and then whatever variable I specify. I have
my x axis varying over several degrees longitude and I want my z to range
over the height in km from the below my topography (so negative heights) up
to several km in the atmosphere (it will be about -7km to 40km). My control
file has the vertical grid specified as cartesian. I'm also confused about z
and lev and which is 1-40 (the number of vertical levels I have), and which
is height. What happens now when I try to plot I either get a line plot of
topography and then a separate plot of the variable on top, or I get an
error message saying "Varying Z dimension environment...but the requested
variable has no Z dimension". Does anyone know if it's possible to plot
something like this where I can see the topography over this area shaded or
boxed out and then the variable contoured above it? Thank you all in advance
for any help you might have.
-Morgan Silverman