dot distribution map

The image is a dot distribution map of the population distribution in the United states also known as the "nightime map". Dot distribution maps portray quantative data as a dot which represents a percentage of the phenomenon found within the boundary of a geographic location.

location found at:http://www.google.com/imgres?imgurl=http://www.census.gov/geo/www/mapGallery/images/small2kden.jpg&imgrefurl=http://www.census.gov/geo/www/mapGallery/2kpopden.html&usg=__DQYIq6tt5cvG7k3Lb6e4sxuO1eY=&h=805&w=1043&sz=433&hl=en&start=2&sig2=adwK1BubLlOyAbHpo60VsA&tbnid=aZJnyA7V6TLovM:&tbnh=116&tbnw=150&ei=iXZTTPj7IcO78gaB-cmVAw&prev=/images%3Fq%3Ddot%2Bdistribution%2Bmap%26hl%3Den%26sa%3DG%26biw%3D1276%26bih%3D579%26gbv%3D2%26tbs%3Disch:1&itbs=1http://