Citizens as sensors: the world of volunteered geography


In recent months there has been an explosion of interest in using the Web to create, assemble, and disseminate geographic information provided voluntarily by individuals. Sites such as Wikimapia and OpenStreetMap are empowering citizens to create a global patchwork of geographic information, while Google Earth and other virtual globes are encouraging volunteers to develop interesting applications using their own data. I review this phenomenon, and examine associated issues: what drives people to do this, how accurate are the results, will they threaten individual privacy, and how can they augment more conventional sources? I compare this new phenomenon to more traditional citizen science and the role of the amateur in geographic observation.

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  1. Brown, M. C. (2006). Hacking Google Maps and Google Earth. New York: Wiley.

    Google Scholar 

  2. Butler, D. (2006). Virtual globes: The web-wide world. Nature, 439, 776–778.

    Article  Google Scholar 

  3. Estes, J. E., & Mooneyhan, W. (1994). Of maps and myths. Photogrammetric Engineering and Remote Sensing, 60, 517–524.

    Google Scholar 

  4. Fernández-Armesto, F. (2006). Amerigo: The man who gave his name to America. London: Weidenfeld and Nicolson.

    Google Scholar 

  5. Goodchild, M. F., Fu, P., & Rich, P. (2007). Sharing geographic information: An assessment of the geospatial one-stop. Annals of the Association of American Geographers, 97(2), 249–265.

    Article  Google Scholar 

  6. Johnson, S. (2006). The Ghost Map: The story of London’s most terrifying epidemic, and how it changed science, cities, and the modern world. New York: Riverhead.

    Google Scholar 

  7. Monmonier, M. (2006). From squaw tit to whorehouse meadow. Chicago: University of Chicago Press.

    Google Scholar 

  8. National Research Council (1993). Toward a coordinated spatial data infrastructure for the nation. Washington: National Academies Press.

    Google Scholar 

  9. National Research Council (2007). Successful response starts with a map: improving geospatial support for disaster management. Washington: National Academies Press.

    Google Scholar 

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Correspondence to Michael F. Goodchild.

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Goodchild, M.F. Citizens as sensors: the world of volunteered geography. GeoJournal 69, 211–221 (2007).

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  • Geographic information
  • Web 2.0
  • Virtual globe
  • Privacy
  • Citizen science