Structuring a Wayfinder's Dynamic Space-Time Environment

Michael Hendricks,

Max Egenhofer, and

Kathleen Hornsby
Conference on Spatial Information Theory (COSIT '03), Kartause Ittingen, Switzerland, Lecture Notes in Computer Science, Vol. 2825, Springer, pp. 75-92, September 2003.

Abstract

To obtain and maintain situational awareness in dynamic space-time environments, wayfinderÕs must project possible future states from current conditions. It has been found, however, that people often do not project into the future when making decisions, but rely instead on current system states. To address this limitation, this paper proposes an approach to structure the space-time environment of a wayfinder by extending into the temporal domain, space partitioning symbolic projection techniques for route planning and integrating the approaches of space-time prisms and geospatial lifelines. To create this structure, the limitation of the wayfinder's maximum travel speed is projected through space-time, from the start point and set all of barriers and compulsions. This process results in a partition of the wayfinder's space-time environment into spaces that can be described in a cognitively plausible manner with the modal verbs can, may, must, and should. The creation of this structure along with these descriptive semantics creates a rich representation of the wayfinder's space-time environment and allows for reasoning about space-time decision points and their impact on future possibilities. To highlight the key points of this approach, a simple wayfinding scenario is presented and its structure created and described with modal verbs.

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