手法を比較

	Network Distance Analysis	Flow Mapping Analysis
分野	Human Geography	Human Geography
系統	Process / pipeline	Process / pipeline
提唱年	1959	1987
提唱者	Edsger W. Dijkstra (shortest-path foundation)	Flow cartography tradition (computer migration mapping by Waldo Tobler)
種類	Measurement of distance and travel cost along a network rather than straight-line	Cartographic technique for visualizing movement between origins and destinations
原典	Dijkstra, E. W. (1959). A note on two problems in connexion with graphs. Numerische Mathematik, 1(1), 269–271.	Tobler, W. (1987). Experiments in migration mapping by computer. The American Cartographer, 14(2), 155–163.
別名	Shortest-Path Analysis, Network Travel-Cost Analysis, OD Cost Matrix Analysis, Routing Distance Analysis	Flow Map, Origin-Destination Mapping, Movement Mapping, Flow Cartography
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.	Flow mapping analysis visualizes movement between places — migrants, commuters, trade, traffic — by drawing the flows of an origin-destination matrix as lines on a map, with line width scaled to the volume moving along each link. It is the cartography of interaction: where choropleths show what is in a place, flow maps show what travels between places, and the central challenge is to reveal the dominant patterns of movement without the map dissolving into an unreadable tangle of crossing lines. The technique was put on a computational footing by Waldo Tobler's 1987 experiments in computer migration mapping, and modern methods add edge bundling, smoothing, and statistical filtering to manage visual complexity.