Figure 4

Detecting mobility patterns. To illustrate the different ways to uncover mobility patterns from CDRs, let us focus on the motion of an individual in Brussels, as measured by his GPS. In this small experiment, the user took his car in Watermael and went to two shops, one in Auderghem and one in Waterloo. The three locations are plotted in red. Three phone calls were made. One at home, one on the highway, and one in Waterloo. An approach where a path is composed of successive position measurements is shown in pink. In contrast, an approach where paths are based on important locations would detect the stop in Waterloo, rightly discard the one on the highway, but would still be blind to the location in Auderghem, because that stop was too short.