I've just been writing a little post on my games dev/art/blog about using procedural functions for terrain creation. Almost as soon as i'd finished I found your pdf and I just wanted to say how great it is, very informative and thorough. I'll pop back and link it soon. Its really great to see indie developers sharing knowlege like this and presenting it in a language that isnt too obscure for the amateur coders to have a crack at it. Anyway, keep up the good work and keep making the good games!