The story of Gall–Peters · 1855 · 1973

Gall–Peters

Equal areas, and a debate about how we see the world.

Explore Gall–Peters →
Geographic grid · Classic orientation
The stronger line marks the equator.

Why this map exists

Equal areas, and a debate about how we see the world.

Keep relative areas correct in a rectangular world map. This supports comparisons of country sizes while accepting changes to their shapes.

How the idea developed

  1. 1855

    James Gall’s earlier proposal

    James Gall proposed the equal-area projection now associated with both names in 1855. It is also known as Gall orthographic, which should not be confused with the familiar circular orthographic view of Earth.

    Blue Marble Geographics · Gall–Peters

  2. 1973

    Arno Peters brings renewed attention

    Arno Peters promoted his world map in 1973, apparently having developed it independently. It became associated with arguments about social justice and how maps represent the world. That public debate is part of its history, alongside Gall’s earlier work.

    Mapthematics · Gall–Peters origins and use

  3. The wider family

    One choice among equal-area maps

    Gall–Peters is a cylindrical equal-area projection with standard parallels at 45° north and south. Different standard parallels give other members of that family; an equal-area map can also have an entirely different outline, as Mollweide does.

    PROJ · Cylindrical equal area

What you gain. What changes.

What stays true

Relative area throughout the map. In the classic orientation, scale is true along the parallels at 45° north and south.

What changes

Shapes elongate vertically near the equator and flatten near the poles. Correct area does not ensure correct distances or local angles.

Projection properties: PROJ · Cylindrical equal area

A common misunderstanding

Gall–Peters is not the only equal-area projection, and Mercator is not a failed version of it. They preserve different properties. The best choice depends on what the map is meant to communicate.

What changes in a country-centered view?

These historical descriptions refer to the classic orientation. MapStudy can rotate the projection’s reference frame so the place facing you becomes the center. The projection still preserves its defining property, but references to the equator, poles, and navigation do not transfer unchanged to the rotated view. Geographic latitude and longitude lines may curve.

The unfolding animation illustrates a mathematical transition. The intermediate shapes are not separate named projections, and Earth is not physically peeled into this map.

See the idea for yourself

Can two very different maps both preserve area?

  1. Unfold Earth into Gall–Peters alongside Mollweide.
  2. Within each map, compare the pale circles at different locations. Look for equal areas and changing shapes.
  3. Explain why choosing between these maps involves more than deciding which one is “accurate.”
Open this experiment ↗

Opens in another tab so you can keep the steps nearby.

Full guided activity →Classroom worksheet →

Sources & further reading

The history and explanations are original MapStudy writing based on the references linked above. Uncertain origins are identified as such. We credit the projection’s creators and later advocates; MapStudy’s contribution is this interactive learning experience.

Our diagrams use the same spherical equations as the explorer. They show geographic grids, not historical source material.