It gives a basic idea, but I think something like Cities:Skylines where you can create maps using a height map and then get the topography lines in a 3d space where you can actively shift the camera around to see them overlaid from any angle would probably help people grasp the idea.

Having said that, I'm now imagining drone footage overlaid with the height maps as an additional resource to standard topographical maps. Would be neat if somebody could create software that could calculate and overlay the height maps in real-time using the drone's altimeter or something.