Gall–Peters projection

This is a special map.

It shows our whole world. This map shows the real size of lands. Some maps make places look too big. This map is different.

Two men helped make it. One man was James Gall. The other man was Arno Peters.

It can look a bit strange. Some shapes on the map look stretched. But the sizes are correct.

Many schools use this map. It helps kids see the world. It is a very helpful tool.

The Gall–Peters projection is a special way to make a world map.

Most maps change the size of lands. This map is an equal-area map. This means it shows the real size of places. It does not make some lands look bigger than they are. However, it does change the shapes of the lands. Some shapes may look stretched out.

Two men are named for this map. James Gall described it in 1855. Arno Peters shared it with many people in the 1970s.

This map caused a big debate. Arno Peters said other maps make rich places look too large. He felt his map showed the true size of Africa and South America. Many groups liked this idea. Some schools and groups like UNESCO use it now.

In the United States, some places use it too. Boston Public Schools began using these maps in 2017. In 2024, Nebraska passed a law for schools to use it. It is a tool to help us see the world's real scale.

The Gall–Peters projection is a special way to draw a map of our world.

Most maps are not perfect because the Earth is a round ball. When we try to flatten a ball onto a flat sheet, things change. This map is called an equal-area projection. This means it shows the true size of different lands. If one country is much larger than another, this map shows that correctly. However, it does change the shapes of the continents. Some landmasses might look taller or more stretched than they really are.

This map works by using a math rule called a cylindrical projection. Imagine wrapping a tall tube around the Earth. The map is drawn on the inside of that tube. In this specific version, the tube is stretched to double its length. This stretching is what keeps the areas of the lands accurate. The map does not change everything the same way. There are two specific lines, at 45° north and 45° south, where there is no distortion. Along these lines, the shapes and distances stay very close to the truth.

Two different men helped create this map over a long time. A Scottish clergyman named James Gall first described it in 1855. He shared his ideas at a big science meeting in Glasgow. He later published his work in a magazine in 1885. Many years later, a German filmmaker named Arno Peters made a similar map. He showed his version to the world in 1973. He called it the "Peters World Map." The combined name, Gall–Peters, was used by Arthur H. Robinson in 1986.

This map became very famous because it started a big argument. Arno Peters believed that other common maps were not fair. He said common maps made wealthy places like Europe look too large. He felt this made poorer places like Africa look too small. Many groups agreed with him and began using his map. However, some map experts disagreed with his claims. They said his map changed shapes too much. They also noted that he claimed it was the only correct map, which was not true.

Even with the old arguments, many people use this map today. The United Nations group UNESCO promotes it to show real sizes. Many schools in Britain use it to teach students about the world. In the United States, Boston Public Schools started using it in 2017. In 2024, the state of Nebraska passed a law for its schools. This law requires them to use the Gall–Peters map or a similar one. It helps students see how large different parts of our planet really are.

The Gall–Peters projection is a rectangular, equal-area map projection. It is a way to represent the spherical Earth on a flat surface. Like all map projections, it must deal with distortion. Because the Earth is a sphere, you cannot flatten it without changing something. This specific projection is a cylindrical equal-area projection. This means it prioritizes the correct size of landmasses over the correct shape of continents.

To understand how it works, imagine a cylinder wrapped around the Earth. The map is created by projecting the surface of the sphere onto this vertical cylinder. In the Gall–Peters version, the cylinder is stretched to double its length. This stretching is a specific mathematical process. It ensures that the area of any region on the map matches its true relative size on the globe. This type of map is known as an equal-area projection. However, this accuracy comes at a cost. The shapes of landmasses become highly distorted, often appearing stretched vertically.

The projection does not distort everything equally. There are specific regions where the map is most accurate. These are called standard parallels. For the Gall–Peters projection, the standard parallels are 45° N and 45° S. Along these two lines, there is no distortion. At these latitudes, both shapes and distances match the stated scale. As you move away from these lines toward the equator or the poles, the shapes change more significantly.

The history of this map involves two different men. James Gall, a Scottish clergyman, first described this projection in 1855. He presented it at a science convention in Glasgow. He later published a formal paper on it in 1885. He originally called it the "orthographic" projection. Much later, in 1967, a German filmmaker named Arno Peters created a similar projection. He introduced his "Peters World Map" to a wide audience in 1973. The combined name, Gall–Peters, was first used by Arthur H. Robinson in 1986.

Arno Peters made the map famous through a major controversy. He argued that common maps, like the Mercator projection, were politically biased. He claimed the Mercator projection made wealthy areas like Europe and North America look too large. Meanwhile, he said it made poorer regions like Africa and South America look too small. Peters promoted his map as a superior alternative for social justice. He even claimed it was the only "area-correct" map. These claims were inaccurate, as many other equal-area projections existed.

The cartographic community responded with significant hostility. Experts criticized Peters for his inaccurate claims about the map's properties. They noted that his map had extreme distortions of shape. They also pointed out the irony of his map. It showed the mid-latitudes, including Peters's native Germany, with little distortion. However, it distorted the low latitudes where many developing nations are located. This led to a deep divide between Peters's supporters and professional map makers.

Despite the scientific debates, the Gall–Peters projection remains widely used today. It is promoted by UNESCO to help people visualize the actual relative sizes of global regions. Many schools in the United Kingdom use it as a standard tool. In the United States, Boston Public Schools began using these maps in 2017. Recently, the state of Nebraska passed a law in 2024. This law requires public schools to display the Gall–Peters projection or a similar equal-area map. It continues to serve as a tool for teaching the scale of our world.