Where is Germany? According to the maps we used in elementary school Geography class, it’s in the middle of Europe. But it’s not. It’s near the northwest corner.
Greenland and Africa are roughly the same size, right? Wrong. Africa is actually fourteen times the size of Greenland. That’s shown accurately by the map on the left, but not the one on the right. The size distortion, and other inaccuracies, are characteristic of the Mercator Projection, the one on the right. It’s the one most of us saw on the walls of our elementary school.
A “projection” in the field of cartography is the method of representing the content of the Earth’s spherical surface on a flat surface. However, no flat map can represent all aspects of a spherical surface correctly, so there are many projections; each one represents selected aspects accurately or conveniently to serve particular needs. Other things are, unavoidably, distorted. Notice how much smaller Greenland, Canada and Alaska are, on the left-hand map. That one shows relative sizes accurately.
In 1569, Gerardus Mercator published a projection that makes lines of longitude and latitude straight and mutually orthogonal, thereby making it easier for the European mariners of his time to use celestial navigation when crossing large oceans. His projection also shows shapes accurately, but not sizes or relative positions except near the equator. Many schools have switched to other projections in recent years, but Mercator maps are still used widely by mariners and airline pilots today.
A projection promoted by Dr. Arno Peters, who claims to have devised it (more about that in a footnote) shows both size and position accurately, though not shape: Any flat projection of a spherical surface must choose between size and shape accuracy.
The most recent objection regarding the Mercator projection is that it distorts in a way that undersizes the “third world” countries. The claim is that since we so often judge things based on size, Mercator devalues those countries. Even placing the northern hemisphere at the top of the map makes that hemisphere seem more important. (Some advocates have actually suggested reversing the positions.)
The Peters projection has
stirred strong controversy*,
much of it fueled by its claimed developer, Peters, himself. However, it is unlikely to come into wide
use, particularly because projections have been developed that strike a balance among the accurate
representations of size, shape and position.
One example is the Robinson projection shown above. Of course, it has its shortcomings: Notice the horizontal stretching of the Earth’s shape, and the fact that most lines of latitude and longitude do not cross at right angles.
So you have the choice: Do you want accurate shape, size, location, or something else? Whatever you want, there’s now a projection that will supply it.
But if you want it all, use a globe.
* More than a century before Peters published his “new” projection, English clergyman James Gall had published the same projection in the Scottish Geographical Magazine. In an interview, Dr. Peters claimed that he had never heard of the Gall projection prior to inventing his. Nonetheless, many refer to the Peters projection as the Gall-Peters projection.
The material in this article is based on information from sources including George Simons International, www.about.com, and others.
W. A. Shapiro