Findings: Phone call friends use the city similarly, and you have a higher chance of running into a friend if you live in the suburbs.
Method: mapping ellipse-shaped polygons of where people make/receive calls in Jiamusi China, and those of his or her phone call friends.
Good for: if you have a geolocated social network and you want to learn more about who uses which parts of the city, and whether the city is set up for friendships. Hospitality focused companies could choose locations based on where interactions are most likely to happen.
