What does a Mercator projection map show

Politically correct world maps in schools are intended to smooth out distorted world views

US schools want to decolonize the curriculum - starting with the Mercator projection

Since March 2017, world maps in the Boston school district that were created using the Mercator projection have been replaced by maps based on the Gall-Peters projection. This should now become the new standard.

Reason: The Mercator projection distorts the relative sizes and positions of the continents, causing Europe and North America to swell to absurd sizes and at the same time to shrink South America and Africa. Developing countries would be devalued, while the importance of the developed nations would be unduly emphasized. Peters projection: a fair world map that heralds an era marked by universal humanism - or a distorted image that markets dismay?

This realisation is not new. And to want to chalk Mercator now, at least overshoots the mark. Because its projection was primarily used for navigation. Your big advantage: For the first time, routes with a fixed compass course can be entered as straight lines on the maps.

For centuries, mathematicians had endeavored to transfer points on a curved spherical surface to a non-curved plane, in such a way that distances and directions could be read from the resulting maps, while at the same time maintaining the area relationships.

It was not until 1827 that Carl Friedrich Gauß showed that it was fundamentally impossible to create maps of the earth's surface that were both length, area and angle. The following applies: the purpose of the map determines the choice of projection, which, whatever its nature, will always be a compromise.

Mercator's projection is conformal - the result is an exaggeration of the area of ​​the regions further away from the equator. North America and Europe appear larger than South America and Africa, and Greenland looks roughly the size of Africa, when in fact it is about 14 times smaller. Mercator was aware of this: he had reserved his projection for use by seafarers and did not use it in his geographical maps, such as those found in the atlas published in 1595 a year after his death.

Those in charge see the Boston Action as the beginning of a three-year effort to decolonize the public school curriculum. With the question of a politically correct map projection, they tie in with a controversial debate of the 1970s and 1980s, which was believed to have meanwhile died down.

The educators hope that the historical and socio-political message of the Mercator card will be rewritten and the exaggeration of the size of the imperialist powers will be put to an end. They fear negative consequences for students who see inaccurate representations of areas in which their heritage is rooted. A few decades ago, at least cartographers, at least, thought little of whether the Peters projection that has now been brought into position is the appropriate means of choice.

Peters projection: ideologically charged, hardly usable cartographically

In 1974 the German historian Arno Peters published his projection. The idea was not new, but a revival of the projection published in 1855 by the Scotsman James Gall, which, however, had been forgotten.

Peters wanted to give the continents their "true dimension" and thereby counteract the "Eurocentric way of thinking" for which the Mercator projection stood in his eyes: designed to secure the power of the European colonial rulers. First Mercator projection from 1569, the first world map to use an angular projection. The well-known Flemish cartographer Gerardus Mercator designed this map primarily to aid navigation on the colonial trade routes. Peters was bothered by their alleged Europe-centering, which, however, goes back to his own trick. Map displays on the Internet still work mainly with the Mercator projection.

Ironically, it is precisely the industrialized countries of the temperate latitudes that appear most lifelike in their representation, in contrast to the developing countries, which were supposed to do justice with Peter's map and which now appear extremely deformed.

The Peters projection provides representations that are true to area, position and axis: All areas are on the same scale, locations of the same width or length lie on horizontal or vertical lines. Peter's argument that his map restores its true proportions to poorer countries led to its dissemination in school, religious and social institutions, and it was also used in public relations by aid organizations. According to his own account, Peters had sold 15 million tickets by the mid-1980s. But the distortion of the shapes of the continents ultimately meant that Peter's map could not prevail, even if it is seen every now and then.

Cartography has other projections in its arsenal, which meet Peters' request and take into account real areas near the equator in an aesthetically pleasing manner. Like Eckert's equal-area projections at the beginning of the 20th century. Or the Mollweide projection from 1805, which shows the earth's surface true to area on an ellipse, at the expense of distortions of shapes and angles that arise with the distance from the equator and prime meridian.

Mediating drafts try to balance out the errors of other world maps and thus arrive at an approximately correct representation of the earth's shape, such as the Wagner projections or the Robinson projection presented in 1961. The Winkel-Tripel-Projektion from 1921 is considered to be a successful compromise between surface and angular accuracy. It is one of the most commonly used projections today. What's next?

The Boston School District has 125 schools and 57,000 students, 14% of whom are white. The largest groups are Latinos and African Americans. After the card swap, the educators want to turn to other topics that are suitable to move away from the presentation of the story from the dominant white perspective.

The Mercator projection maps will not be removed, but all newly purchased maps will be based on the Peters projection. Teachers who confront their students with the results of both projections report aha-moments.

The decision on this project was made internally and was not put up for public discussion. The educators hope to find numerous imitators - in the United States and beyond.

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