When you picture a map of the Earth, you’re picturing something that looks like this:
But what if we told you that every map you see is actually wrong? If you look at the map above, you’ll notice something interesting about the sizes of the countries and continents. Take the island of Greenland on the map for instance. If you were to compare it with the continent of Africa, you’ll see that the two are roughly the same size. But in reality, Greenland is much, much smaller than Africa. Almost 14 times smaller, actually. In fact, in this map, all of the countries near the poles are portrayed as being much larger than they really are.
Even India appears to be much smaller than it actually is. On the map, Europe appears to be bigger than India but if one were to actually transpose India over Europe at keeping the size to scale (as seen below), India would swallow almost all of Western Europe along with some parts of Norway and Russia too!
Why does this happen?
The problem lies in the fact that maps are two-dimensional representations of a three-dimensional planet. The fact is that the surface of a sphere cannot be represented as a plane without some form of distortion. This was proved by the mathematician Frederich Carl Gauss a long time ago. Ever since cartographers (people who make and study maps) and mathematicians have been looking for ways to best bridge this representational gap. To do this, they use something called a projection.
Based on the method used to project the three-dimensional features of our planet on a flat surface, each project has its own shortcomings. Whether it is shape, distance, direction or land area, each map can only show some of these features accurately while compromising on the others. The map that you see above for instance, is drawn with something called the Mercator projection. This is the most common projection used for maps and is what we have all commonly seen growing up.
The Mercator projection is used because it is simply convenient and has many advantages. The projection preserves the shape of all the countries and continents without distorting them. It also preserves direction and this is why it was used in olden days for navigation. On a Mercator map, the line drawn between two points would provide the exact angle that can be traced by a compass, thus making it easy to navigate. It also has latitudes and longitudes that are straight lines at rectangles, which makes it even easier to calculate angles for navigation.
But this convenience of the Mercator projection comes at a cost. It distorts the land areas of the countries as shown in the example between Africa and Greenland above. But the Mercator map is still so widely used that even Google Maps uses it to give accurate directions.
Meanwhile, if you want to see a map where the sizes of the countries are accurate in relation to each other, you can check out the Gall-Peters projection shown below. This is called an equal-area map. As you can see in the image, this projection also has its own problems. While the land areas of the countries are quite accurate, their shapes are completely distorted.
Starting in the late 1960s, map-making advanced to a whole new level. We began to explore space by launching satellites that could accurately monitor the Earth, its size, shape and many geographic features. We invented GPS, the Global Positioning System, which uses these satellites to accurately pinpoint your location in most places across the globe. Cartographers started doing away with the old projections due to their lack of accuracy. Today, mathematicians and cartographers have a wide library of projections, each useful for a specific purpose.
But cartographers aside, us common people still use the Mercator projection widely because of its convenience. It’s the map that we have all seen in school across during Geography class. Ultimately, it wouldn’t be accurate to say that all maps or wrong. There’s no such thing as the right projection for all purposes. Each one has its own advantages and can be used for a specific purpose. So the next time you look at a map, remember that there is more than meets the eye!
Did you enjoy reading about maps and projections? Here are some more related topics you may find interesting:
[custom_author=Suraj Prabhu ]
Suraj is a self-proclaimed audiophile and a jack-of-all-trades writer with a diverse set of interests. An amateur quizzer on the side, he claims that the first object he fell in love with was a book on flags at age 3. His favourite punctuation mark is the Oxford Comma, which coincidentally happens to be one of his favourite songs too!
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