Compressed Transmission of Route Descriptions

TL;DR

This paper introduces two novel methods for compressing route descriptions in road networks, aiming to reduce transmission costs and time, especially useful for mobile server-based routing with limited bandwidth.

Contribution

The paper proposes two new compression techniques for route descriptions, combining via edges/nodes and contraction hierarchies, and discusses their application to mobile routing systems.

Findings

Methods are promising but not yet evaluated with real data.

Compression can potentially enable route transmission over low-bandwidth connections.

Combines existing concepts like via edges/nodes and contraction hierarchies in novel ways.

Abstract

We present two methods to compress the description of a route in a road network, i.e., of a path in a directed graph. The first method represents a path by a sequence of via edges. The subpaths between the via edges have to be unique shortest paths. Instead of via edges also via nodes can be used, though this requires some simple preprocessing. The second method uses contraction hierarchies to replace subpaths of the original path by shortcuts. The two methods can be combined with each other. Also, we propose the application to mobile server based routing: We compute the route on a server which has access to the latest information about congestions for example. Then we transmit the computed route to the car using some mobile radio communication. There, we apply the compression to save costs and transmission time. If the compression works well, we can transmit routes even when the bandwidth is low. Although we have not evaluated our ideas with realistic data yet, they are quite promising.