Dorling Cartogram is a visual guide to understanding geographic data. It uses a unique method of mapping data that allows for a more accurate representation of the underlying geographic information. This guide will provide an introduction to the Dorling Cartogram method, as
From Wikipedia
A cartogram is a thematic map of a set of features, in which their geographic size is altered to be directly proportional to a selected variable, such as travel time, population, or gross national income. Geographic space itself is thus warped, sometimes extremely, in order to visualize the distribution of the variable. It is one of the most abstract types of map; in fact, som be called diagrams. They are primarily used to display emphasis and for analysis as nomographs.