Structuring a Wayfinder's Dynamic Space-Time Environment

To travel successfully in a dynamic space-time setting, wayfinders must project the impact of a changing environment onto future travel choices. When making decisions, however, people often fail to consider the impact of future changes. They instead overly rely on current system states. In addition, spatial information systems designed for wayfinders typically focus on current or historic travel information. To address these limitations, this paper presents an approach to structure the dynamic space-time environment of a wayfinder. With this structure, improved spatial information systems can be designed to support wayfinders in dynamic environments. To create this structure, four primitives of space-time wayfinding are presented: maximum travel speed, a starting point, barriers, and compulsions. Combining the speed limitation with each of the remaining three primitives creates distinctive partitions of spacetime. To integrate all four primitives, a method of sequentially partitioning space-time is described which results in four partition categories that account for the different constraints of wayfinding. These partitions are described in a cognitively plausible manner using 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.