Compare methods

	Time Geography Analysis	Accessibility Analysis
Field	Human Geography	Human Geography
Family	Process / pipeline	Process / pipeline
Year of origin	1970	1959
Originator	Torsten Hägerstrand	Walter G. Hansen
Type	Framework for representing individual movement and constraints in space and time	Spatial index of the ease of reaching opportunities from a location
Seminal source	Hägerstrand, T. (1970). What about people in regional science? Papers of the Regional Science Association, 24(1), 6–21.	Hansen, W. G. (1959). How accessibility shapes land use. Journal of the American Institute of Planners, 25(2), 73–76.
Aliases	Hägerstrand Time Geography, Space-Time Path Analysis, Space-Time Prism Analysis, Time-Space Geography	Hansen Accessibility, Gravity Accessibility Measure, Potential Accessibility, Spatial Accessibility Index
Related	4	4
Summary	Time geography is a framework, introduced by Torsten Hägerstrand in 1970, that represents human activity as continuous trajectories through a joint space-time coordinate system rather than as static points on a map. Each individual traces a space-time path through the 'space-time aquarium', and the set of all locations that can be reached and returned from within a time budget forms a space-time prism, whose spatial footprint is the potential path area. The framework grounds accessibility and mobility in the inescapable fact that people can be in only one place at a time and that movement consumes both space and time.	Accessibility analysis measures how easily opportunities — jobs, shops, clinics, parks — can be reached from a given location, combining the attractiveness (size) of destinations with the cost of travelling to them. The gravity-based formulation introduced by Walter Hansen in 1959 sums the opportunities at all destinations, each discounted by a distance-decay function of travel cost, producing a single accessibility score per origin that has become a foundational concept in transport geography and urban planning.