Computational agents and urban life spaces: a preliminary realisation of the time-geography of student lifestyles

This paper is part of a research initiative that seeks to investigate the interactions between urban structure, life styles and individual spatial choice. In so doing, it seeks to advance our treatment of the concepts of accessibility and location in urban space. The paper itself adopts Hägerstrand's Time Geography as an organising framework and proceeds to deploy GIS and other tools of computational geography to create routine realisations of individuals' action volumes and potential life lines. It then attempts to create an aggregate picture from these. The paper aims to translate earlier work on a discrete cellular implementation of Hägerstrand's geometric conceptualisation of space and time into an improved treatment of access and interaction.

Hägerstrand's concepts of the life-line and time-space prism, and consequent derivations from these, have provided a means of interpreting an individual's opportunities and constraints in space, and have simultaneously questioned the wisdom of separating time from space in evaluating accessibility and location. The current paper reports on research in progress at the University of Auckland, which attempts to operationalise and generalise these core concepts of Time Geography in the context of student life styles. The initial goal is to provide easier access to the insights available from Hägerstrand's view of the individual, but the long term aim is to develop means of dealing with aggregate phenomena, an area that traditional Time Geography developed only theoretically.

Specific individual models are developed for the case of university students in Auckland, New Zealand. Simplified daily paths are developed for these students through rule-based selection using real-world opportunities and constraints. Key components of the daily paths specified include access to home, work and study in specific locations. The concept of the space-time prism is used to identify discretionary opportunities and action volumes for students. In order to create an analytical structure to manipulate these life-lines and prisms a discrete, three-dimensional model of urban space-time is utilised. Approximately 20 students' daily life-lines are generated to form the basis for assessment of the technique.

Building on these individual life-lines the paper goes on to develop a means of expressing the aggregate manifestation of student activity, including the potential for interaction between students, work and campus sites. A number of spatial parameters of the system are described, including measures of opportunity and access in different parts of the study area. The paper reports on the range of behaviours of the surrogate students that form the basis of the current model, and on aspects of actual student geographies in Auckland. Extensions and areas of practical application in the context of changing university structures are discussed.