An intersection-based trajectory-region movement study

In order to better understand the movement of an object with respect to a region, we propose a formal model of the evolving spatial relationships that transition between local topologies with respect to a trajectory and a region as well as develop a querying mechanism to analyze movement patterns. We summarize 12 types of local topologies built on trajectory-region intersections, and derive their transition graph; then we capture and model evolving local topologies with two types of trajectory-region strings, a movement string and a stop-move string. The stop-move string encodes the stop information further during a trajectory than the movement string. Such a string-format expression of trajectory-region movement, although conceptually simple, carries unprecedented information for effectively interpreting how trajectories move with respect to regions. We also design the corresponding Finite State Automations for a movement string as well as a stop-move string, which are used not only to recognize the language of trajectory-region strings, but also to deal effectively with trajectory-region pattern queries. When annotated with the time information of stops and intersections, a trajectory-region movement snapshot and its evolution during a time interval can be inferred, and even the relationships among trajectories with respect to the same region can be explored.