手法を比較

	Flow Mapping Analysis	Cartogram Construction
分野	Human Geography	Human Geography
系統	Process / pipeline	Process / pipeline
提唱年	1987	2004
提唱者	Flow cartography tradition (computer migration mapping by Waldo Tobler)	Cartogram tradition (diffusion method by Gastner & Newman; circular method by Dorling)
種類	Cartographic technique for visualizing movement between origins and destinations	Map transformation that rescales region area to represent a variable
原典	Tobler, W. (1987). Experiments in migration mapping by computer. The American Cartographer, 14(2), 155–163.	Gastner, M. T., & Newman, M. E. J. (2004). Diffusion-based method for producing density-equalizing maps. Proceedings of the National Academy of Sciences, 101(20), 7499–7504.
別名	Flow Map, Origin-Destination Mapping, Movement Mapping, Flow Cartography	Value-by-Area Map, Area Cartogram, Density-Equalizing Map, Anamorphic Map
関連	4	4
概要	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.	A cartogram is a map in which the area of each region is rescaled so that it is proportional to some variable — population, votes, GDP — rather than to its true geographic size. The aim is to correct the visual bias of ordinary maps, where large but sparsely populated regions dominate the eye while small, populous ones nearly vanish, by making each region as big as the quantity it represents. Cartogram construction is the family of techniques that produce these value-by-area maps, ranging from contiguous density-equalizing diffusion to non-contiguous circle and rectangle methods, each balancing the accuracy of areas against the recognizability of shapes.