1. 15 th ACM GIS: Seattle, WA: Nov 7—9, 2007 TS2-Tree: An Efficient Similarity Based Organization for Trajectory Data Petko Bakalov Eamonn Keogh Vassilis J. Tsotras University of California Riverside {pbakalov,eamonn,tsotras}@cs.ucr.edu

2. 15 th ACM GIS: Seattle, WA: Nov 7—9, 2007 Similarity queries between trajectory objects are important – What is the number of commuters which have similar trajectories to the proposed bus line? – Which bus line suits me best for my anticipated trip? Problem: Traditional methods for trajectory indexing do not preserve the global picture of the trajectory. In the poster, we present a novel indexing technique TS2-tree which: – Clusters trajectories according to their similarity – Preserves global view of the trajectory – Provides upper and lower bound estimations of the distances between trajectories Need for TS2-tree?

3. 15 th ACM GIS: Seattle, WA: Nov 7—9, 2007 Trajectory Envelope – a key component in TS2-tree. Trajectory envelopes are organized hierarchically into a height balanced tree structure similar to an R-tree or B-tree. – The structure is completely dynamic: The insert and delete operations can be intermixed with search ones. The similarity search becomes a top down traversal of the tree guided by the upper and lower bound estimations. More details will be provided in our poster. TS2-tree structure