2D Topographic Maps VS 3D DEMs

Some of the more notable features in WI.       Some of the more notable features in WI.

The contour lines on a USGS-topoquad are a two dimensional representation of the third dimension. A digital elevation model captures this surface through an array of points. Study the two images above and see if you notice the correlations. The digital elevation model has been vertically exaggerated by a factor of two.