手法を比較

	Public Participation GIS (PPGIS)	Accessibility Analysis
分野	Urban Studies	Human Geography
系統	Process / pipeline	Process / pipeline
提唱年	2006	1959
提唱者	Renee Sieber (synthesizing 1990s NCGIA work)	Walter G. Hansen
種類	Participatory integration of local spatial knowledge into GIS	Spatial index of the ease of reaching opportunities from a location
原典	Sieber, R. (2006). Public participation geographic information systems: A literature review and framework. Annals of the Association of American Geographers, 96(3), 491–507.	Hansen, W. G. (1959). How accessibility shapes land use. Journal of the American Institute of Planners, 25(2), 73–76.
別名	PPGIS, Participatory GIS, PGIS, Volunteered Geographic Mapping	Hansen Accessibility, Gravity Accessibility Measure, Potential Accessibility, Spatial Accessibility Index
関連	4	4
概要	Public participation GIS (PPGIS) is a family of practices that bring the spatial knowledge, values, and priorities of ordinary people into geographic information systems, so that community perspectives sit alongside expert and official data in planning and decision-making. Synthesized as a field by Renee Sieber in 2006, it ranges from facilitated workshops where residents mark up paper maps to web mapping platforms where thousands of people drop points marking places they value or fear. Its aim is both technical and political: to enrich spatial analysis with local knowledge and to widen who gets to shape decisions about place.	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.