Cartogram

cartogram [′kärd·ə‚gram]

(mapping)

A type of single-factor or topical map that is often diagrammatic to show traffic flow, movement of people or goods, or value by area, where areas of the political subdivisions are distorted so that their size is proportional to their monetary value.

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Cartogram 

a map that shows the average intensity of a phenomenon for individual regions (units) of the territorial division shown on the map.

For example, a cartogram may characterize the average population density or the extent of plowed land (average hectares of arable land per hundred hectares of total land area) according to country, region, or district. To make the map easier to read, each territorial unit is colored or hachured according to the computed intensity of the phenomenon in it, so that the density of the coloring or hachures reflects this intensity.

Cartograms are especially widely used for graphic reproduction of statistical data on population and agriculture. A shortcoming of cartograms is that they do not show differences in the intensity of the phenomena within each territorial unit; this problem is lessened by a further territorial division.