Attached Link: http://www.ridgecrest.ca.us/~jslayton/terrain.html

On to Toolkits-

Here's mine currently. All are FREE except VistaPro. You don't need VistaPro for these above operations- but I keep it around since I started with VP back in the late 80's with MS-DOS.

The most Powerful of the free terrain tools in MICRODEM. It is a bit complicated but for basic file conversions you don't really need to know how the program works. Reading the HELP files however is a GREAT education in the What's- What in Digital Mapping and Terrain file formats. The handy blue HTML link shows where to get ALL these programs...

MICRODEM

http://www.usna.edu/Users/oceano/pguth/website/microdem.htm

WILBUR is my second favorite, because like MICRODEM, it reads NED BIL files (I will explain further down).

http://www.ridgecrest.ca.us/~jslayton/wilbur.html

3DEM is my third in use.

http://www.visualizationsoftware.com/3dem.html

READ the help files-manuals with these programs and you will get a great education in digital mapping, terrain data manipulation, etc. But their PRIMARY function is to act as FILE CONVERSION UTILS as there a a LOT of terrain formats and it DOES get very confusing for newbies.