Reading the Landscape: Unlocking Contour Lines

Imagine you are a pilot flying over the Lake District in northern England. Below you, you can see rolling hills, sharp peaks, and deep valleys — but if you looked at a flat paper map, how could you possibly tell where the high ground is? Maps are flat. The real world is not. Here is the puzzle: cartographers — people who make maps — need a way to show three-dimensional landscape on a two-dimensional piece of paper. Think about that for a moment. How would YOU do it? Shade the high bits darker? Use tiny mountain drawings? Both of those methods were actually tried in history — but neither told you exactly how high something was, or how quickly the ground climbed. There had to be a better answer.