Unclassed Choropleth Map

An unclassed map has as many classes as there exist unique data values in the distribution. However, not all of these classes may be necessary if the map reader cannot discriminate among the graphic values representing unique numerical values. The map on the left is a classed map and the map on the left is an unclassed map showing population change in percentages. The advantage and disadvantage for unclassed choropleth maps is that it minimizes the amount of generalization and simplification.

http://go.owu.edu/~jbkrygie/krygier_html/geog_353/geog_353_lo/geog_353_lo07.html