MAPPING FREQUENCY DISTRIBUTIONS BY THE BOX-AND-WHISKER
J. Trenton Kostbade · The Professional Geographer · 1981
The box-and-whisker diagram, described here, is a simple but effective device for portraying frequency distributions clearly, accurately, and fully. It is a useful means for providing legends and category divisions for choropleth maps, being capable of handling skewed distributions without suppressing the skewness. Maps are used to illustrate the utility of the method for examining different types of distributions and for making map comparisons to discover relationships among variables.