
251Insights and Knowledge Discovery
12.4.2.1 Single-User Data
We conducted several experiments on the trajectory of a single GeoLife user’s mobil-
ity history. Raw single-user trajectory GPS points are inputted into our trajectory
extraction algorithm (Algorithm 12.1). During the extraction process, we avoid huge
amounts of redundant trajectory traces by setting T
s
= 2 min. Since the GeoLife data-
set has a sampling rate of 2 s, after the residence mode of each point in the single-
user GeoLife dataset has been determined, as described in Section 12.2.6, points
tagged as PM within each T
s
intervals are discarded. Since the GeoLife dataset con-