Medial-axis-based cartograms

Cartographers and geographers were making cartograms for centuries before digital computers and displays became available. In data visualization, an area cartogram distorts a map by resizing its regions according to some external geography-related parameter, such as population or epidemiological data. Cartograms are difficult to draw by hand because it´s difficult to simultaneously optimize shape and area error while preserving the original map´s topology. Automated methods for drawing cartograms have therefore received considerable interest. A method for generating cartograms that combines iterative relocation of a map´s vertices with medial-axis-based transformations retains the input map´s topology.