Help with gradients as topography

[Jonathanengr]

I'm doing a conceptual drawing for a land development company, and wanted to do color gradients based on the topography of the land (like you see on maps). I have a topographic survey of the property with 5-foot contours, so is there a way to do gradients based on this information? Thanks!

[Jonathanengr]

Okay, after browsing the forums, I'm using a mesh and have had some success doing what I want. However, I'm having a hard time with the colors being "slight" changes as they grow darker. Is there a way to choose two colors of brown, green or whatever, and generate a color palette with dozens of shades in-between the two so I can create a smoother transition? I love the way the gradient tool does this transition from one color to the other, and would love to grab the little gradient scale it makes and use it as a palette.