In GIS, how is a 'cartogram' defined?

A cartogram is defined as a type of thematic map in which the geometry of regions is distorted in order to convey information about an attribute other than land area. This means that the size of each area on the map is scaled according to a specific variable, such as population, income, or any other statistical measure. Consequently, regions may appear larger or smaller than their actual geographic size, highlighting disparities and making it easier to compare data visually.

The focus of a cartogram is on visualizing the importance of particular attributes, rather than accurately representing geographic space. For instance, if a population cartogram is created, countries or states with larger populations will occupy more space on the map, while less populous areas will shrink, effectively conveying the distribution of population in a compelling visual manner. This feature makes cartograms a powerful tool for understanding demographic or economic information in a geographic context.

Other definitions, like those focusing solely on road networks, random samples of geographic features, or classifications of demographic data, do not capture the essence of what a cartogram is designed to accomplish. Cartograms emphasize the variable being represented rather than geographical accuracy, differentiating them from traditional maps that maintain conventional spatial representations.