Equal Earth: equal areas, different shapes

A familiar world, with a different area rule

The idea grew out of news in 2017 that Boston Public Schools was switching its classroom world maps to Gall–Peters. That projection preserves area, but makes tropical continents look elongated from north to south. The researchers wanted an alternative that kept area proportions while making continent shapes easier to read. Gall–Peters is not the only equal-area projection.

Bojan Šavrič, Tom Patterson and Bernhard Jenny introduced Equal Earth in 2018. They drew inspiration from Robinson’s familiar rounded outline and balanced appearance. Robinson, however, does not preserve area. Equal Earth sought a similarly readable world map while adding that specific requirement.

An attractive outline alone does not tell you whether area is preserved. When reading a classroom map or comparing countries, check the projection name and its stated property before using screen space as evidence of geographic size.

Sources: PROJ · Equal Earth (Šavrič, Patterson & Jenny, 2018) · Esri ArcUser · Equal Earth design background (Winter 2019) · Šavrič, Jenny & Patterson · Equal Earth: design, adoption and impact (2019)

Equal does not mean equally shaped

Imagine two pieces of paper with the same area: one can be wide and short, the other narrow and tall. Equal area does not require equal shape. A map projection has a similar distinction, although its transformations are governed by geographic coordinates rather than a freehand stretch.

On Equal Earth, a country near the edge may look bent or wider than expected. That can coexist with correct relative area. If a shape seems surprising, compare it with the globe before assuming its amount of land has changed.

Sources: Library of Congress · Geospatial reference data: projection properties

Ask an area question, not every question

Equal Earth is useful for questions such as “Which of these regions contains more land?” It does not make a ruler placed anywhere on the world map an accurate distance tool. Nor should a straight line drawn between two cities automatically be treated as the shortest journey.

Compare land footprints here. For travel distance, use a geodesic distance calculation; for an actual itinerary, use a suitable route service. A convincing-looking world map cannot measure all three accurately.

Sources: Library of Congress · Geospatial reference data: projection properties

Try Greenland beside Brazil

Find Greenland and Brazil at the same zoom. Mercator enlarges high-latitude Greenland, which can make the difference between the two feel smaller. Equal Earth lets you inspect Brazil’s broad outline and Greenland’s relative size under a consistent area scale.

Move Greenland between the center and the edge of the flat view. Its shape changes, but its share of map area at a common scale is retained. Countries at different latitudes get the same amount of map space for the same amount of ground.

Sources: PROJ · Equal Earth (Šavrič, Patterson & Jenny, 2018)

Common questions