Efficient fastest-path computations for road maps  

作　　者：Renjie Chen Craig Gotsman 

机构地区：[1]University of Science and Technology of China,Hefei,China [2]New Jersey Institute of Technology,Newark,NJ,USA

出　　处：《Computational Visual Media》2021年第2期267-281,共15页计算可视媒体（英文版）

基　　金：supported by the Anhui Provincial Natural Science Foundation(2008085MF195);the National Natural Science Foundation of China(62072422);Zhejiang Lab(2019NB0AB03).

摘　　要：In the age of real-time online traffic information and GPS-enabled devices,fastest-path computations between two points in a road network modeled as a directed graph,where each directed edge is weighted by a“travel time”value,are becoming a standard feature of many navigation-related applications.To support this,very efficient computation of these paths in very large road networks is critical.Fastest paths may be computed as minimal-cost paths in a weighted directed graph,but traditional minimal-cost path algorithms based on variants of the classical Dijkstra algorithm do not scale well,as in the worst case they may traverse the entire graph.A common improvement,which can dramatically reduce the number of graph vertices traversed,is the A*algorithm,which requires a good heuristic lower bound on the minimal cost.We introduce a simple,but very effective,heuristic function based on a small number of values assigned to each graph vertex.The values are based on graph separators and are computed efficiently in a preprocessing stage.We present experimental results demonstrating that our heuristic provides estimates of the minimal cost superior to those of other heuristics.Our experiments show that when used in the A*algorithm,this heuristic can reduce the number of vertices traversed by an order of magnitude compared to other heuristics.

关 键 词：shortest-path road map HEURISTIC GPS navigation A^(*)search 

分 类 号：U491[交通运输工程—交通运输规划与管理] O157.5[交通运输工程—道路与铁道工程]