Querying Numeric-Constrained Shortest Distances on Road Networks

Mingyu Yang, Wentao Li, Wei Wang, Dong Wen, Lu Qin

Abstract: In real-world road networks, edges possess additional numeric attributes, such as width and toll, in addition to length. Incorporating these additional attributes enhances the functionality of shortest-distance services. To this end, current research on shortest-distance computation requires that the numeric attributes of edges on a path exceed a lower bound $l$ (within the interval [l,oo]). However, it often overlooks the benefits of setting an upper bound $r$ (within the interval [l, r]). To bridge this gap, we introduce the numeric-constrained shortest-distance query problem, which enforces interval constraints [l, r] on the numeric attributes of edges on a path. There are two intuitive solutions: the Online-Search method, which excludes edges that violate the constraints during the search, leading to inefficient query responses, and the Full-Index method, which creates an index for each necessary interval constraint [l, r], resulting in excessive space consumption due to numerous potential intervals. Our novel index-based method, which uses the tree decomposition technique and exploits interval-distance relationships, aims to mitigate these issues. As confirmed by our experimental results, our method greatly improves query speed - over 20 times faster than Online-Search- and consumes less space than Full-Index.