A Whole New World

Which is bigger: Russia or Africa? When asked, many would confidently answer that Russia is the biggest. And given that Russia appears to stretch from Europe, all the way to the far-right end of Asia, such an assumption really isn’t that absurd. However, in reality Africa is the larger of these two landmasses. In fact, it is so large that you could fit in most of Europe, the United states, China and India and still have space left over!

True size of Africa.
Source: Wikimedia commons

So why does our knowledge regarding the correct size and shape of a country appear to be so wrong? Enter: The Mercator projection.

The Mercator projection

Named after its inventor, Flemish geographer and cartographer – Gerardus Mercator, the Mercator map projection was created in 1569. Contrary to how it is currently used, Mercator didn’t create his projection with geography students in mind. Nor did he anticipate that it would become one of the most prevalent forms of mapping in the world. This is because the Mercator projection intentionally alters the size and shape of the countries so that they are completely wrong. So then, what was the incentive for creating such a “wrong” map?

The man himself: Gerardus Mercator.
Source: Wikimedia commons

Coinciding with the period in which Gerardus Mercator was born was the “Age of Exploration”. Many sailors during this period required a tool that would allow them to explore the seas, and would ideally prevent them from getting lost. Although sailors had been using maps prior to Mercator, cartographers at the time appeared to be far more invested in making their maps aesthetically pleasing than functional.

Such maps were correct in regard to the shape and size of countries, but they were difficult to navigate with. This is because that due to the curvature of Earth, sticking true to shape and size came at the expense of angularity. So, unless you were travelling directly from East to West, it was very likely that your ship would eventually tangent away from the course plotted on your map. To counter this, sailors had to obsessively recalculate their bearings to ensure that they didn’t become another causality of the ocean.

Mercator realised this conflict of interest, and so deviated from the standard model of mapping to create his own technique now known as the Mercator projection.

How was the Mercator projection created?

To create his map, Mercator first mapped the features of Earth onto a sheet of paper via a method called cylindrical projection. Techniques such as cylindrical projection allow us to represent 3D spherical objects (like Earth) onto a 2D plane (example: a sheet of paper). But, the resulting 2D picture doesn’t quite capture the depth of the 3D object. This results in surface shape and size distortion.

However, although there was obvious distortion in the size and shape of his countries, the lines of latitude (horizontal) and longitude (vertical) now always intersected each other at a 90-degree angle. This formed somewhat of a 2D grid of Earth. Still, this alone would be no different from the maps of earlier cartographers as angularity was still an issue.

Cylindrically projecting Earth. Notice how the lines of latitude and longitude intersect at 90 degree angles.
Source: Wikimedia commons

But this is where Mercator made his breakthrough. He realised that by progressively increasing the distance between the lines of latitude as he moved away from the equator (in accordance with his mathematical formula), he could remove this problem of angularity almost entirely.

The common Mercator projection.
Source: Wikimedia commons

Thanks to Gerardus Mercator, now any straight line that was plotted onto his map using a certain bearing stayed true to reality. So, if your map told you to sail from point A to point B at a 45-degree angle – you can be guaranteed that you will arrive at your destination by travelling along a 45-degree straight line in reality.

Now, sailors no longer had to account for the curvature of the Earth when following a certain mapped route, and so, no longer did they have to obsessively correct their course. Not only would this have made navigation more efficient, but it would have also made sailing much safer for inexperienced sailors.

Even today, the significance of the Mercator projection is realised as we still use it in many of our navigational systems. If you’ve ever used Google maps, you’d notice that it too uses the Mercator projection to guide us to our favourite coffee shop. Although Gerardus Mercator may not have realised it at the time, his simple innovation has undoubtedly withstood the test of time to become one of the most important, albeit underrated, inventions of the last millennium.

2 Responses to “A Whole New World”

  1. Nadun Udawela says:

    Hi Andre!
    Thanks for your comment

    I assume that the Mercator projection has fallen somewhat out of favour ever since the advent of GPS systems. However many online mapping tools such as Google maps still do employ some variation of the Mercator projection.

  2. Andre Chambers says:

    Nice post! I always wondered why Greenland is bigger than Africa on world maps..
    Do you think that the Mercator projection is still relevant nowadays since everyone just uses GPS to navigate?