What would a map of the world look like if your only source of data was the half-billion users of Facebook? Paul Butler, an intern on Facebook’s data infrastructure engineering team set about answering that question. Butler took a sample of 10 millions pairs of Facebook friends and plotted their locations. The raw geocoding alone of the home locations of the sample set produced rough and identifiable outline of the continents of the world. To get a more refine map, Butler further experimented, explaining:
Instead I found a way to simulate the effect I wanted. 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. I used a color ramp from black to blue to white, with each line’s color depending on its weight. I also transformed some of the lines to wrap around the image, rather than spanning more than halfway around the world.
Of course, the boldest and best defined countries are those where Facebook is most popular and the population is dense. On viewing the map, the eyes are drawn towards the brighter areas demarking the United States, Europe, India, and Asia. There Russia and China are noticeably dark along with sections of Brazil and Northern/Central Africa.
Visit: Visualizing Friendships