Range graded proportional circle map

Range graded proportional circle map is similar to the variable circle map in that it uses different size circles to display changing sets o value. However in this map there is usually only one set of data being displayed and as in the variable circle map the larger the circle the larger the data set. These maps are particularly good because they let the cartographer use variance in  the symbol size so captures more than just the magnitude of the numbers. This range fraded circle map represents the population of europe.

Link: http://www.d.umn.edu/geog/cartfolder/HTML%20Pages/Prop-Symbol2.htm