手法を比較

	Suitability Analysis	Accessibility Analysis
分野	Urban Studies	Human Geography
系統	Process / pipeline	Process / pipeline
提唱年	1969	1959
提唱者	Ian L. McHarg	Walter G. Hansen
種類	Spatial multi-criteria mapping of land suitability for a given use	Spatial index of the ease of reaching opportunities from a location
原典	McHarg, I. L. (1969). Design with Nature. Natural History Press. ISBN: 9780471114604	Hansen, W. G. (1959). How accessibility shapes land use. Journal of the American Institute of Planners, 25(2), 73–76.
別名	Land Suitability Mapping, Overlay Suitability Analysis, Weighted Overlay Analysis, Suitability Modelling	Hansen Accessibility, Gravity Accessibility Measure, Potential Accessibility, Spatial Accessibility Index
関連	4	4
概要	Suitability analysis maps how well each parcel of land supports a proposed use — housing, conservation, a highway, a landfill — by combining the relevant physical, ecological and accessibility factors into a single composite score. In the tradition established by Ian McHarg's 1969 Design with Nature, each factor is captured as a map layer, reclassified onto a common suitability scale, and overlaid so that places good on many factors stand out from places that are not. The result is a suitability surface that makes the trade-offs in a land-use decision explicit, transparent and defensible.	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.