Modeling with purpose

Models are used to simplify complex systems. Take a modern city as an example; you will see that it consists of intricately linked systems such as highways, electrical grids, and transit systems. While these systems operate in the same physical territory, they require very different models to help us understand them. For example, a subway system snakes and curves below a city’s varied terrain, but our model of it—a subway map—uses straight lines and places stations at nearly equidistant intervals. The subway map is not the city—it is a selective simplification of the city that makes it easier for passengers to visualize their journey. The transit map is a model so ubiquitous that it’s hard to imagine doing it any other way—yet it took time to evolve.

The subway map, as we know it today, was invented by Harry Beck in 1931 while re-designing the map used by the London Underground. The old design was confusing to riders...