I'm above 60 degrees latitude, so I have to use local DEM files. I've been using the same DEM files for a few years now, and I thought I'd see what else is out there. USGS offers digital elevation models at 1/3 arc second resolution, but in some formats (IMG, ArcGrid, GridFloat) that I wasn't able to make work.
Does TF require that the DEM file has the .dem extension, or are other data types accepted?
Thanks
Tom