jenks71: Illinois 1959 county gross farm product value per acre
Description
Classic data set for the choice of class intervals for choropleth maps.
Usage
data(jenks71)
Arguments
source
Jenks, G. F., Caspall, F. C., 1971. "Error on choroplethic maps: definition, measurement, reduction". Annals, Association of American Geographers, 61 (2), 217--244