I would add that elevation map can help in defining a management zone. We have a couple fields that look as though there is a soil or fertility problem, but once we compared the yield map, the soil map and the elevation maps, we realized we have a sloped area that runs water off of it and thus starves the corn for water. Keep in mind we are in a desert and pivot irrigate. So to fix that we are gonna chisel on the contour to help hold water on the slope.