One thing working on big data has done is to sensitize us to the power of visualization, especially using maps. Here is one that impresses, especially in view of our focus on urban development: Data viz extraordinaire Max Galka created this map using NASA’s gridded population data, which counts the global population within each nine-square-mile patch of Earth, instead of within each each district, state, or country border. Out of the 28 million total cells, the ones with a population over 8,000 are colored in yellow. That means each yellow cell has a population density of about 900 people per square mile—“roughly the same population density as the state of Massachusetts,” Galka writes in the accompanying blog post. The black regions, meanwhile, reflect sparser population clusters.