#VistaPro
There's a third-party product for the Amiga version of Vista that will
convert an Amiga IFF graphic into a Vista DEM. Scapemaker is its name, I
think. I don't think it's available in a PC version. In any case, if you
had an Amiga and an aerial photo of your region, you could digitize it
into an IFF image, then convert the image via Scapemaker into a DEM and
you'd be set. Maybe you could get someone with an Amiga to do this for
you, of course.