Range Graded Proportional Circle Map

http://personal.frostburg.edu/mtmaier0/maps.htm

Range graded proportional circle maps use circles instead of dots to proportionally show increases in data. Unlike continuously variable symbols, there are a set number of range graded symbols and each symbol is assigned a specific range of values. The above map represents traffic fatalities in the United States (by State) in 2009 using proportional circles for the given data values.