Cartogram

A cartogram (also called a value-area map or an anamorphic map, the latter common among German-speakers) is a type of thematic map where the geographic size of areas (like countries or provinces) is distorted to reflect a specific variable, such as population, GDP, or travel time. This makes it easier to visualize data patterns.

Types

Contiguous Cartograms – Shapes are distorted, but areas remain connected.
Non-contiguous Cartograms – Shapes maintain their form but are resized and may be separated.
Diagrammatic Cartograms – Replace areas with simple geometric shapes (circles, squares).
Mosaic Cartograms – Divide areas into small equal-sized units, like hexagons or squares.
Linear Cartograms – Adjust the length of lines to represent variables like travel time.

History

The first cartogram was made in 1876 by Pierre Émile Levasseur, using squares to represent European countries by population, economy, and religion.
Hermann Haack and Hugo Weichel (1898) created the first contiguous cartogram in Germany.
Waldo Tobler (1963) developed one of the first computer algorithms for cartograms.

Uses

They make it easier to compare values visually.
They highlight regional differences more clearly than standard maps.
Commonly used in election results, economic data, and population distribution maps.

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Vineesh V, Geography

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