Visualizing and Analyzing Activities in an Integrated Space-Time Environment

Abstract

An integrated space-time environment is demanded by activity-based travel studies to facilitate the investigation of spatial and temporal characteristics of activities. The current geographic information system (GIS), which has been successful in supporting trip-based travel analysis, does not include an explicit time representation and therefore is incapable of supporting activity-based travel analysis efficiently. This study proposes a temporal GIS design that incorporates the space-time path concept of Hägerstrand's time geography to facilitate the analysis of activities in a space-time context. The space-time path concept provides an efficient approach to organizing activities and travels in their space-time contexts and to supporting the investigation of spatiotemporal relationships between individuals. This study adopts the three-dimensional orthogonal space-time system in the temporal GIS design and develops representation and analysis functions related to space-time paths and individual activities. The proposed design is successfully implemented in a prototype system. The system provides an integrated space-time environment to effectively visualize activities and travels in their space-time contexts and analyze their spatiotemporal characteristics. Such a system offers useful tools to facilitate activity-based travel studies.