Choropleth Maps on High Resolution CRTs: The Effects of Number of Classes and Hue on Communication.

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Elisabeth S. Nelson, Associate Professor (Creator)
The University of North Carolina at Greensboro (UNCG )
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Abstract: The research reported here was designed to determine how quickly and accurately map readers viewing choropleth maps on a high-resolution computer monitor are able to identify to which class an areal unit on the map belongs, when the map has between four and eight classes and is produced in shades of either gray, green or magenta. As expected, accuracy rates decreased and reaction times increased as the number of classes on the map increased, Accuracy rates ranged from 91.9% for four-class maps to 68.2% for eight-class maps (averaged for all three colors used in the study). Hue also affected accuracy rates and reaction times, the best results being obtained with achromatic (gray-shaded) maps: 84.5% correct, averaged over all numbers of classes. Maps shaded with magenta proved to be the least satisfactory with an accuracy rate of 72.8%. The study provides cartographers with empirical guidelines regarding what level of map-reading accuracy might be expected for choropleth maps designed with a given number of map classes, in a specific hue, and displayed on a high-resolution graphics monitor.

Additional Information

Cartographica, v. 26(2): 40-52.
Language: English
Date: 1990
Color recognition, Visual searching, Map making, Color codes, Grey

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