Time Geography and Space–Time Prism

Time geography is a constraints‐oriented approach to understanding human activities. Time geography highlights the necessary (though not sufficient) spatial and temporal conditions required for human activities. It also provides an elegant framework for incorporating these conditions into individualistic and ecological analyses and models of human behavior. Two central concepts in time geography are the space–time path and prism. The path represents actual mobility (real or simulated) and the prism represents potential mobility in space with respect to time. Developed as a conceptual framework in the 1960s by Torsten Hägerstrand, analytical time geography has emerged in response to growing capabilities to collect and analyze data on mobile objects and human activities. There is a rich collection of measures and procedures for analyzing space–time paths and prisms in planar space, constrained by networks and through velocity fields. There are also methods for representing virtual interaction via information and communication technologies. Emerging are methods for mobility data mining and knowledge discovery.