I've played around with bryce a while ago, and I think it might work pretty well for the effect you want to achieve.
Even the older Bryce version 4 had a simple but rather powerful terrain editor - you can imort gray scale images, edit with a brush, add filters like eroded cliffsides or smoothed out hillsides. very fun to use and very intuitive.
The down side of this is that it would be comp generated, and a lot less cool than your current hand drawn style.
Anyway Riven was one of my favourite games, and It was great looking around your site!
Yea... you are real strong on the mountains/rocks. they look superb! The thing is that they are far better detailed than some of the other set dressing such as the roads and bridges/ship. The wood planks need some grundging up, but it's the same with the rest of the walking surfaces. As an example, in http://sandman.net/media/modules/art...IslandMap2.png, the docks and ship need just a bit more attention to make it look like individual planks instead of like a solid color with lines drawn on it to represent planks. It's kind of like you spent 10 hours on the mountain side/cliff faces and then 10 minutes slapping the other elements down. The other elements would be ok IF the mountains were not so detailed in comparison, but then it would not be as great a piece as a whole either.
I hope this does not come off harsh as I CAN see that you have the skill as demonstrated by the mountain work you have done already.
Thanks a lot for your comments! :)
I agree with everyone's recommendations to stick with the hand drawn erosion which not only looks nice, but seems to better fit the aesthetic of a personal journal anyway. But what I'd really like to know is why nobody has repped you yet?!? Seriously, I've looked through both the Myst and the Riven journals and they are a real work of art. This is one of the best fan-art projects I've seen. So I guess I have the privilege of being the first to add to your reputation (Yeah +2...) here at the Guild. Anyway, keep up the good work.
If you're really looking to work with greyscale heightfields and some sort of automatic erosion process, you might want to take a look at a combination of Terragen and Wilbur. Wilbur (http://www.ridgenet.net/~jslayton/wilbur.html) has the erosion processes you might be looking for (Precipitation based and Incise Flow along with other editing features) while Terragen can generate photo-realistic renders of your terrains. I use both fairly frequently, particularly with maps depicting smaller areas.