手法を比較

	Network Distance Analysis	Accessibility Analysis
分野	Human Geography	Human Geography
系統	Process / pipeline	Process / pipeline
提唱年	1959	1959
提唱者	Edsger W. Dijkstra (shortest-path foundation)	Walter G. Hansen
種類	Measurement of distance and travel cost along a network rather than straight-line	Spatial index of the ease of reaching opportunities from a location
原典	Dijkstra, E. W. (1959). A note on two problems in connexion with graphs. Numerische Mathematik, 1(1), 269–271.	Hansen, W. G. (1959). How accessibility shapes land use. Journal of the American Institute of Planners, 25(2), 73–76.
別名	Shortest-Path Analysis, Network Travel-Cost Analysis, OD Cost Matrix Analysis, Routing Distance Analysis	Hansen Accessibility, Gravity Accessibility Measure, Potential Accessibility, Spatial Accessibility Index
関連	4	4
概要	Network distance analysis measures how far apart places are along a real network — roads, paths, rails — rather than as the crow flies, recognizing that movement is constrained to edges and junctions. Its engine is the shortest-path problem solved by Dijkstra's 1959 algorithm, which finds the least-cost route between locations over a weighted graph and scales up to origin–destination cost matrices between many points. Network distance and travel time are the realistic inputs to accessibility, routing, location, and flow analyses, and their ratio to straight-line distance — the detour or circuity index — itself diagnoses how indirect a network is.	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.