Compare methods

	Catchment Area Analysis	Accessibility Analysis
Field	Human Geography	Human Geography
Family	Process / pipeline	Process / pipeline
Year of origin	1964	1959
Originator	David L. Huff (probabilistic formulation)	Walter G. Hansen
Type	Delineation of the geographic area served by a facility	Spatial index of the ease of reaching opportunities from a location
Seminal source	Huff, D. L. (1964). Defining and estimating a trading area. Journal of Marketing, 28(3), 34–38.	Hansen, W. G. (1959). How accessibility shapes land use. Journal of the American Institute of Planners, 25(2), 73–76.
Aliases	Trade Area Analysis, Service Area Delineation, Market Area Analysis, Catchment Delineation	Hansen Accessibility, Gravity Accessibility Measure, Potential Accessibility, Spatial Accessibility Index
Related	4	4
Summary	Catchment area analysis delineates the geographic area that a facility — a shop, hospital, school, or station — actually serves, turning the abstract question of 'who uses this place?' into a mapped polygon. Methods range from the simplest fixed-radius buffer through nearest-facility (Voronoi) tessellation and network drive-time isochrones to David Huff's 1964 probabilistic model, in which patronage is shared among competing facilities by their relative attractiveness and distance. The choice of method reflects how strictly customers are tied to the nearest centre and how much competition and travel cost shape real behaviour.	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.