Timetable Nodes for Public Transport Network
- URL: http://arxiv.org/abs/2410.15715v2
- Date: Wed, 23 Oct 2024 05:02:39 GMT
- Title: Timetable Nodes for Public Transport Network
- Abstract summary: Faster pathfinding in time-dependent transport networks is an important and challenging problem in navigation systems.
We propose a method that advances graph-based approaches by using different optimization techniques from computational geometry.
Our solution suits any other time-dependent networks and can be integrated into other pathfinding algorithms.
- Score: 31.793066412010468
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Faster pathfinding in time-dependent transport networks is an important and challenging problem in navigation systems. There are two main types of transport networks: road networks for car driving and public transport route network. The solutions that work well in road networks, such as Time-dependent Contraction Hierarchies and other graph-based approaches, do not usually apply in transport networks. In transport networks, non-graph solutions such as CSA and RAPTOR show the best results compared to graph-based techniques. In our work, we propose a method that advances graph-based approaches by using different optimization techniques from computational geometry to speed up the search process in transport networks. We apply a new pre-computation step, which we call timetable nodes (TTN). Our inspiration comes from an iterative search problem in computational geometry. We implement two versions of the TTN: one uses a Combined Search Tree (TTN-CST), and the second uses Fractional Cascading (TTN-FC). Both of these approaches decrease the asymptotic complexity of reaching new nodes from $O(k\times \log|C|)$ to $O(k + \log(k) + \log(|C|))$, where $k$ is the number of outgoing edges from a node and $|C|$ is the size of the timetable information (total outgoing edges). Our solution suits any other time-dependent networks and can be integrated into other pathfinding algorithms. Our experiments indicate that this pre-computation significantly enhances the performance on high-density graphs. This study showcases how leveraging computational geometry can enhance pathfinding in transport networks, enabling faster pathfinding in scenarios involving large numbers of outgoing edges.
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