Research of Spatio-Temporal Access Method
Jinjin Zhao · Computer Technology and Development · 2008
Spatiotemporal database is an important branch in the research field of database.After about ten year's development,researchers have made significant progress in areas of spatiotemporal ontology,spatiotemporal model,spatiotemporal query optimization and index.Many entities in real world have both spatial and temporal characteristics,such as parcels in land management systems,vehicles in traffic management systems and so on.As more complicated applications concerning these entities appear,it is necessary for modern database management systems to be capable of providing efficient means to manipulate spatiotemporal data.Spatiotemporal database is used to manage objects that change their locations and shapes as time passes.It is essential to build effective spatiotemporal indices in order to improve query performance because of the huge mount of spatiotemporal data in the applications.Describes a new spatiotemporal access method(SEST-Index) that combines two approaches for modeling spatiotemporal information: snapshots and events.This method makes it possible to not only process time slice and interval queries,but also queries about events.The SEST-Index implementation uses an R-tree structure for storing snapshots and a log data structure for storing events that occur between consecutive snapshots.Experimental results that compare SEST-Index and HR-tree show that,for a change frequency between 1% and 13%,SEST-Index requires less storage space than HR-tree,and for a change frequency between 1% and 7%,SEST-Index outperforms HR-tree for interval queries.In addition,as SEST-Index is an event-oriented structure,event queries are efficiently answered.