[agracier]

Is it possible to just make a messy canyon or land scape? Ps I am not going for real life just my own thing ya know what I mean?

Of course you can make your own landscape. I'd say it's too much work to be worth the while, but that's just my opinion. In any case you can make totally fictional maps from scratch. No reason why not, if you want to invest the time.

I would suggest you first look at some of the map_h.tga files first, from other maps so that you can get an idea how it works with the 256 RGB gray values and corresponding height.

You'll need a good graphics editor and a more than passing knowledge of what all the different kinds of paint/spray/draw/smooth etc. tools can do, but once you feel confident it's time to go knock yourself out ... and have fun.