Check this out:
I just resurrected and cleaned up an old tool I had lying around. It's now nice and usable by others. This tool loads terrain data, and renders it from the ground, simulating what a human or a camera would see. This is useful for armchair exploring or for identifying peaks. This was relatively novel when I wrote it >10 years ago, but there are a number of similar tools in existence now. This implementation is still useful in that it's freely licensed and contains APIs, so fancier processing can be performed on its output.
Sources and (barely-complete-enough) documentation live here: