Cartograms

A cartogram isn't quite your typical map. In a cartogram, an alternate standard of measurement used for distance or area replaces the traditional one. Often times used to represent the spread of population density or political tendencies, in the example above the cartogram is drawn to represent the distribution of GDP. This is represented by the unrealistic areas of each individual country. The larger the country's size the greater percent of the world's GDP it contributes.

http://www-personal.umich.edu/~mejn/cartograms/