Transit node routing: Difference between revisions

Revision as of 22:02, 28 November 2020

Revision as of 10:11, 8 November 2022

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== Intuition ==

[[File:Transit node routing intuition.gif|thumb|Multiple routes using the same access nodes to long-distance road network.]]

Long-distance travel usually involves driving along a subset of the [[road network]] such as [[Controlled-access highway|freeways]] instead of e.g. urban roads. This sub-network can only be entered by using sparsely distributed access node[[Node (computer science)|snodes]]. When compared to one another, multiple long-distance [[Path (graph theory)|routes]] starting at the same ___location always use the same small amount of access nodes close to the starting ___location to enter this network. In the same way, similar target locations are always reached by using the same access nodes close to them. This intuition only holds for long-distance travel. When travelling short distances, such access nodes might be never used because the fastest path to the target only uses local roads.

Because the number of such access nodes is small compared to the overall number of nodes in a road network, all shortest routes connecting those nodes with each other can be pre-calculated and stored. When calculating a shortest path therefore only routes to access nodes close to start and target ___location need to be calculated.

{{Clear}}

== General framework ==