Nominal Area Choropleth Map

This map was taken from https://courseware.e-education.psu.edu/courses/geog482/policies.shtml

This is a good example of a Nominal Area Choropleth Map.  What makes this different than other choropleth maps is that is does not use categorical or interval/ratio data.  These maps use nominal data where there is no clear hierarchy within the data.  In this case the different minority groups are not necessarily more or less than any other minority group.