Profantasty makes Campaign Cartographer 2, which is a great program, but a
little pricey for average hobbyists.
A great free program called Wilbur will chart an entire globe for you: http://www.ridgenet.net/~jslayton/software.html
It's very technical, and may be a bit tough to get the hang of at first, but
it draws fractal maps with height data.