Route Instructions Based on Topological Stages of Closeness 

Wuersch, M. (1), Caduff, D. (2),

September 23, 2006

1 Intelligent Spatial Technologies
PO Box 3857
Portland, ME 04104, USA
This email address is being protected from spam bots, you need Javascript enabled to view it

2 Department of Geography, University of Zurich - Irchel
Winterthurerstr. 190, CH-8057 Zurich, Switzerland
This email address is being protected from spam bots, you need Javascript enabled to view it

Abstract. Pedestrian Navigation Systems (PNSs) differ from guidance systems for car navigation in many ways (Krüger et al., 2004) and, therefore, demand different requirements (May et al., 2003, Corona and Winter, 2002). The most important difference is that pedestri-ans are not tied to a road network. For instance, pedestrians are free to use network-like systems, such as walkways or streets, but may also switch at will to region-based sys-tems that have no obvious network structure, such as parks, train stations, etc. PNSs that provide route instructions, therefore, need to go beyond network-dependent instructions and adapt to the variability of environments that wayfinders pass through.

Route Instructions for Pedestrian Navigation

Pedestrian Navigation Systems (PNSs) differ from guidance systems for car navigation in many ways (Krüger et al., 2004) and, therefore, demand different requirements (May et al., 2003, Corona and Winter, 2002). The most important difference is that pedestri-ans are not tied to a road network. For instance, pedestrians are free to use network-like systems, such as walkways or streets, but may also switch at will to region-based sys-tems that have no obvious network structure, such as parks, train stations, etc. PNSs that provide route instructions, therefore, need to go beyond network-dependent instructions and adapt to the variability of environments that wayfinders pass through.

We propose a theoretical foundation for the generation of route instructions, which is based on a region-based definition of routes, rather than the typical node-edge-node approach. Defining a route as a sequence of regions detaches the wayfinder from the street network. It further allows tailoring route instructions such that wayfinders may enjoy the freedom of choosing a particular path, as for instance, which side of the street to walk on, or where to cross an open area, such as a park or town square. The focus of this work is on the underlying framework for the generation of route instructions for such pedestrian navigation systems, rather than the presentation of the directions to the navigator. The proposed framework formally describes the relation between navigator and path in terms of topological stages of closeness (SOCs), which enable a finer granu-larity of route instructions, and hence, the generation of more accurate route instruc-tions.