The ability to represent and query continuously moving objects is important in many applications of spatio-temporal database systems. In this paper we develop data structures for answering various queries on moving objects, including range and proximity queries, and study tradeoffs between various performance measures--query time, data structure size, and accuracy of results. 							
						
							
					 															
					Pankaj K. Agarwal, Lars Arge, Jeff Erickson, Hai Y