Dot Distribution Map

http://blog.chicagohistory.org/index.php/2012/02/segregation-in-chicago/

A dot density map is a type of map that uses dot symbols to show the presence of a feature or phenomenon.  Dot maps rely on a visual scatter to show spatial pattern.  The map above is of specific areas of segregation in Chicago.  These ethnic divides are shown by different colored dots.  Red dots symbolize Caucasion, blue is for African Americans, green is for Asian, orange is Hispanic and gray is other.