Necessary space - time conditions for human interaction

Key scientific and application questions concern the relationships between individual-level activities and their effects on broader human phenomena, such as transportation systems and cities. Continuing advances in geographic information science, location-aware technologies, and geosimulation methods offer great potential for observational and simulation studies of human activities at high levels of spatiotemporal resolution. The author contributes by developing rigorous statements of the necessary space - time conditions for human interaction by extending a measurement theory for time geography. The extended measurement theory identifies necessary conditions both for physical and for virtual interaction. The theory suggests elegant and tractable solutions that can be derived from data available from location-aware technologies or geosimulation methods. These conditions and their solutions could be used to infer the possibilities for human interaction from detailed space - time trajectories and prisms generated from observation or simulation studies.