Wired: December 14, 2015
ALL ROADS MIGHT not technically lead to Rome—but, if you happen to be in Europe, the majority of them do.
In a new infographic, designers Philipp Schmitt, Benedikt Groß, and Raphael Reimann set out to answer the centuries-old question of: Do all roads actually lead to the Italian capital?
To find the answer, the designers began by crunching some numbers. First they overlaid a 10,231,707 square-mile grid atop the whole of Europe, and divided it into 486,713 cells. Each cell represented a starting point for a journey beginning within that cell and ending in Rome.
Next, they used a routing engine called GraphHopper and highway data from Open Street Map to create an algorithm that calculated the fastest route between each of the 486,713 starting points and Rome, Italy—which route, Schmitt adds, was not always the most direct. In Norway and Sweden, for example, “you’ll notice that most routes join the biggest freeway at the Swedish east coast instead of driving directly south towards Rome.”
Once they’d mapped all the routes, Schmitt and his team combined their data to see which segments of highway were most heavily trafficked. The more often a given stretch of highway was used, the darker and more prominently it was drawn on the map.
The outcome is beautiful. Roads less traveled feed into high-density thoroughfares that snake through the continent like spider veins, growing thicker and thicker as the roads leading toward the Italian hub become less numerous and more direct. The resulting maps are a little like Nelson Miner’s All Rivers and Ben Fry’s All Roads projects, which use vector-like visualizations to make sense of a dense set of data.
The team decided to do the same for the United States, which is home to no fewer than 10 cities named “Rome.”
The US map is marked by smaller highways feeding into busy interstates like tributaries flowing into larger rivers. “As you may notice from that image, Romes in the US tend to be located more in the east,” says Schmitt. “Seeing this together with the route network led us to speculate about European settlement in the US.”
Given the fact that there’s a city named Rome (or Roma) on almost every continent, you could safely say: “All roads may not lead to Rome, Italy—but if you get creative with your route, many roads do eventually lead to some version of the city’s namesake.” It doesn’t roll off the tongue as nicely as “all roads lead to Rome,” but what it lacks in poetry it makes up for in pedantry.