A safe-exit approach for efficient network-based moving range queries

Query processing on road networks has been extensively studied in recent years. However, the processing of moving queries on road networks has received little attention. This paper studies the efficient processing of moving range queries on road networks. We formulate a network-based concept called safe exits that guarantee the query result of the client remains unchanged before the client reaches any exit. This significantly reduces the communication overhead between moving clients and the server. We then develop an efficient algorithm for computing safe exits for a client on-demand. We evaluate the proposed techniques using real road network data. Experimental results show that our algorithm constructs safe exits efficiently and they effectively reduce the communication cost.