Backbone Index to Support Skyline Path Queries over Multi-cost Road Networks

Qixu Gong, Huiping Cao

Abstract: Skyline path queries (SPQs) extend skyline queries to multi- dimensional networks, such as multi-cost road networks (MCRNs). Such queries return a set of non-dominated paths between two given network nodes. Despite the existence of extensive works on evaluating different SPQ variants, SPQ evaluation is still very inefficient due to the nonexistence of efficient index structures to support such queries. Existing index building approaches for supporting shortest-path query execution, when directly extended to support SPQs, use unreasonable amount of space and time to build, making them impractical for processing large graphs. In this paper, we propose a novel index structure, backbone index, and a corresponding index construction method that condenses an initial MCRN to multiple smaller summarized graphs with different granularity. We also present efficient approaches to find approximate solutions to SPQs. Our extensive experiments on nine real-world large road networks show that our approaches can efficiently find meaningful approximate SPQ solutions by utilizing the compact index. The backbone index can be constructed with reasonable time, which dramatically outperforms the construction of other types of indexes for road networks. As far as we know, this is the first compact index structure that can support efficient approximate SPQ evaluation on large MCRNs.