How Facebook Connects the World: A Visual

A Stunning Visualization of Facebook Friend Connections – Click to Enlarge

This beautiful simulation was created by a Facebook intern named Paul Butler. He is an intern on Facebook’s data infrastructure engineering team.

Using a sample of 10 million friend pairs, he wanted to see how those friends were connected geographically. How did he do it?

He explains in a Facebook note, but it is a little bit technical, so I will attempt to translate for the lay reader.

First he started with his 10 million sample pairs. Then he sorted them out by adding up how many friends each city has with each other. For example, how many friends do people in New York have in Chicago? How many friends do people in Los Angeles have in Tokyo? And so on.

So then he tried plotting lines between those cities. Pairs of cities that had more friends between them would have brighter lines. But this turned out to be a bit of a problem. When he tried this,

…a big white blob appeared in the center of the map. Some of the outer edges of the blob vaguely resembled the continents, but it was clear that I had too much data to get interesting results just by drawing lines. I thought that making the lines semi-transparent would do the trick, but I quickly realized that my graphing environment couldn’t handle enough shades of color for it to work the way I wanted.

His graph simply did not have enough shades of blue to make an accurate representation of the numbers. But since he sounds like a very smart guy, he came up with a solution:

I defined weights for each pair of cities as a function of the Euclidean distance between them and the number of friends between them. Then I plotted lines between the pairs by weight, so that pairs of cities with the most friendships between them were drawn on top of the others.

So cities that were closer together got brighter lines. So the line between New York and Chicago is brighter than the line between Los Angeles and Tokyo. Next, he chose to plot lines between cities that have more friendships between them on top of other lines. So the line from New York to Chicago is plotted on top of the line from New York to Scranton.

And Voila! A really nice map of the world drawn entirely with friendships. Paul Butler had some deep thoughts on it:

It’s not just a pretty picture, it’s a reaffirmation of the impact we have in connecting people, even across oceans and borders.

Facebook has gotten some bad press lately. And frankly, I was getting sick of people clogging up my News Feed with Farmville.

But damn, that picture is cool.