TY - JOUR
T1 - Speeding Up Reachability Queries in Public Transport Networks Using Graph Partitioning
AU - Tesfaye, Bezaye
AU - Augsten, Nikolaus
AU - Pawlik, Mateusz
AU - Böhlen, Michael H.
AU - Jensen, Christian S.
N1 - © The Author(s) 2021.
PY - 2022
Y1 - 2022
N2 - Computing path queries such as the shortest path in public transport networks is challenging because the path costs between nodes change over time. A reachability query from a node at a given start time on such a network retrieves all points of interest (POIs) that are reachable within a given cost budget. Reachability queries are essential building blocks in many applications, for example, group recommendations, ranking spatial queries, or geomarketing. We propose an efficient solution for reachability queries in public transport networks. Currently, there are two options to solve reachability queries. (1) Execute a modified version of Dijkstra’s algorithm that supports time-dependent edge traversal costs; this solution is slow since it must expand edge by edge and does not use an index. (2) Issue a separate path query for each single POI, i.e., a single reachability query requires answering many path queries. None of these solutions scales to large networks with many POIs. We propose a novel and lightweight reachability index. The key idea is to partition the network into cells. Then, in contrast to other approaches, we expand the network cell by cell. Empirical evaluations on synthetic and real-world networks confirm the efficiency and the effectiveness of our index-based reachability query solution.
AB - Computing path queries such as the shortest path in public transport networks is challenging because the path costs between nodes change over time. A reachability query from a node at a given start time on such a network retrieves all points of interest (POIs) that are reachable within a given cost budget. Reachability queries are essential building blocks in many applications, for example, group recommendations, ranking spatial queries, or geomarketing. We propose an efficient solution for reachability queries in public transport networks. Currently, there are two options to solve reachability queries. (1) Execute a modified version of Dijkstra’s algorithm that supports time-dependent edge traversal costs; this solution is slow since it must expand edge by edge and does not use an index. (2) Issue a separate path query for each single POI, i.e., a single reachability query requires answering many path queries. None of these solutions scales to large networks with many POIs. We propose a novel and lightweight reachability index. The key idea is to partition the network into cells. Then, in contrast to other approaches, we expand the network cell by cell. Empirical evaluations on synthetic and real-world networks confirm the efficiency and the effectiveness of our index-based reachability query solution.
KW - Public transport networks
KW - Reachability queries
KW - Spatial network databases
KW - Temporal graphs
UR - http://www.scopus.com/inward/record.url?scp=85112537316&partnerID=8YFLogxK
U2 - 10.1007/s10796-021-10164-2
DO - 10.1007/s10796-021-10164-2
M3 - Journal article
C2 - 35310777
AN - SCOPUS:85112537316
SN - 1387-3326
VL - 24
SP - 11
EP - 29
JO - Information Systems Frontiers
JF - Information Systems Frontiers
IS - 1
ER -