Any plugin or way to identify colours?

I need a way to basically tell the game that a certain green is land, and should be treated as a solid, and a certain blue is water, and shouldn't be able to go in to unless you have a certain item etc etc. Basically I need a way to identify colours and use that to effect the game.

R0J0hound anyway to use canvas for this?

Yes, the canvas plugin has an rgbaAt function that can be used to find the color at any point on the canvas object.