Dot distribution maps

A dot distribution map uses dots to measure the occurence of the data being measured in an area.  The more dots the higher the frequncy of the measured data.  As you can tell from the map here one dot doesn't always have to represent one occurrence as this map uses a dot to measure population in the world at one per 100,000 people.
http://www.bbc.co.uk/scotland/learning/bitesize/standard/geography/population/distribution_density_rev1.shtml