Spatial Search Processes

  • Robert Lloyd
Part of the GeoJournal Library book series (GEJL, volume 39)


Most spatial problems are solved by coordinating multiple tasks. Looking for something in a visual scene is a simple example frequently experienced by people. Lets say you are attending a football game and you know a friend is also at the game. You have an image of your friend encoded in memory and you are searching the stands for a match for that image. What variables make this example an easy or difficult problem? Some variables relate to what is in your memory. Can you construct a good image of what your friend might look like? Did you last see your friend at breakfast or in elementary school? Having accurate information about your friend’s appearance would be a great help in the search. This is called top-down information because it is information in your memory. Does your friend have any unique features that would make her stand out from others in the crowd. Red hair would be more unique than brown hair and green hair would be even better. If she was seven feet tall and had green hair your search would be truly blessed. The information provided by the environment, the colors, shapes, sizes, etc., compete for your attention. This is called bottom-up information because it is information being perceived by your visual system. Your attention can be directed by focusing on important features. You might use size and shape features to focus attention on people who are female and away from those that are male. Your friend may attract your attention immediately if she has something unique about her appearance. You may have to scan each row in the stadium if she looks like most other fans at the football game.


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Copyright information

© Springer Science+Business Media Dordrecht 1997

Authors and Affiliations

  • Robert Lloyd
    • 1
  1. 1.Department of Geography and the Center of Excellence in Geographic EducationUniversity of South CarolinaColumbiaUSA

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