dems arn't tied to Terragen in any way (just was my fav proggy at that time lol )

there a goverment(uni)  thing using satellite data  and is availible in quite a few resolutions and they cover huge chunks of our planet!! (maybe not all ) think it could be a major "selling point" if people could model there own backyard or there fav camping spot

link is to Yale uni so is minimum on ads ;-) and has lots of info on the types of maps etc

http://www.yale.edu/ceo/Documentation/dem.html

have fun (when it isnt fun GET paid for it lol )