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Ok, so I took your advice, Korash, and flipped the contour lines around the deepest pit (with the bridge) to black and shifted the shades in brown to show the deepest of the pits (steps) to be the darkest and then make each successive 'step' lighter until I got to the forest.

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Another variation was when I added a harder edge to them to make them stand out more. I really like the effect.

I think that balancing out what layers were lighter and darker helped to create the sense of topographic layers but I still need work on those contour lines.

Thanks for the help!

-GP