Catchment Area Analysis

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.