Range Queries on Multi-Attribute Trajectories

Motivated by the trend of providing comprehensive knowledge about trajectory data, we study multi-attribute trajectories each of which contains a sequence of time-stamped locations and a set of characteristic attributes. This enriches the data representation by providing a comprehensive description of moving objects and thus enables new types of queries on moving object trajectories. In this paper, we consider answering range queries that return trajectories (i) containing particular attribute values and (ii) passing a certain area during the query time. We integrate standard trajectories and attributes into one unified framework and propose an index structure as well as the query algorithm. The structure is general and flexible in terms of handling both multi-attribute trajectories and standard trajectories, answering a range of queries and supporting update-intensive applications. The evaluation is conducted in a prototype database system and experimental results demonstrate that our method outperforms alternative methods by a factor of 3-10 on a data set of one million real trajectories and synthetic attribute values.