Camden market was chosen for collecting user mobility traces. Camden market is a large craft and clothing market in Camden town and the fourth most popular visitor attraction in London, attracting approximately 100,000 people each weekend (Wikipedia, n.d.). HP GPS rx5730 handheld receiver is used for data collection, with a position accuracy of better than 3 meters most of the time. Users were supposed to keep the GPS receiver with them for as much of their visiting time as possible, with most carrying the GPS receiver in pockets. Occasionally, tracking information has discontinuity mainly when users move inside the indoor part of Camden market where GPS signals cannot be received.
The GPS receiver takes reading of the user’s position every second and records it into a trace log. The trace log contains at least the following data: