Programm to visualize layers

Hi,

We want to write a programm to visualize different data-sets in layers.
For example, soil layers, underground-water layers, etc...

It'd  basically be an extension of our DEMViewer (see
www.geogr.uni-jena.de/~p6taug/demviewer/demv.html) but we suspect that
we couldn't use a Linear2DSet as we used there. In the DEMViewer, height
(of the digital elevation model) is mapped to Display.ZAxis. We also
tried to implement DEMViewer with a Linear3DSet (more or less like in
Galaxy.java) but we gave up after managing to produce (nice) results
with the 2DSet.

The question is (are!): has anyone already written such a programm? Does
any one have an idea? Am I mistaken to suppose that it can olny be done
with a 3DSet? (In this case, I suppose I have to use a IsoContour map so
that different layers have different iso-values.)

The point is that we could also do with a DEMViewer that would show us
TWO (or more!) DEM's at the same time on the same display. From this to
our layer-visualization programm is just another hand full of
code-lines!

Thanks!

Ugo