Brought to my attention, a set of interesting historical examples of visual mapping. It's a very old idea that is still useful to describe a complex system before attempting to improve it with analytics. At the right a clip of an example developed by Isaac Newton.
I often use it as a first step in my work. Followed by data visualization, and then finally with direct mathematical techniques. These are usually in increasing amounts of complexity and cost. The advantage is that you can stop when your improvement goals are achieved. Simple is better.