Taking the census, with cellphones | Science/AAAS | News
▻http://news.sciencemag.org/math/2014/10/taking-census-cellphones
If you want to figure out how many people live in a particular part of your country, you could spend years conducting home visits and mailing out questionnaires. But a new study describes a quicker way. Scientists have figured out how to map populations using cellphone records—an approach that doesn’t just reveal who lives where, but also where they go every day.