Your World Map is Hiding Something

May 26, 2016


Take a look at a map of the world.

If it looks like this one, as most do, you will see that Alaska appears larger than Mexico and that Greenland looks about the same size as Africa.

In reality, Mexico is larger than Alaska and Africa is about 14x the size of Greenland. The maps below show how their true sizes compare (images from The True Size Of).

The “normal” world map is actually very strange
alaska mexico true size
africa greenland true size

Because the world is a sphere, it is impossible to draw it on a flat surface without distorting it in some way. These distortions are known as map projections, the mathematical rules for how to stretch each point on the Earth’s surface onto a 2-dimensional plane.

This particular map uses the Mercator projection, the most popular map projection today and almost certainly the one you are most familiar with. When you imagine the world, the size of each continent and where they sit in relation to each other, chances are your mental image looks like this. But as familiar as this picture of the world may seem, this “normal” map is actually quite strange.

In addition to the distorted sizes mentioned above, the Mercator projection has several other odd features. For one, some parts of the world are missing. Both the top and the bottom of the map are clipped.

If you haven’t done so already…

press the button below the map to “unclip” the bottom and see what’s there

As you move further down the map, the terrain begins to zoom in closer. About halfway down a physical structure appears, the Amundsen–Scott South Pole Station. Further down, the texture of the snow on the ground comes into view, and below that, individual snow flakes.

In theory, the Mercator projection continues on to infinity. If this image were to continue, it would eventually zoom in to the scale of individual atoms and beyond.

This image of the extended Mercator comes from The Mercator Redemption, a 2013 paper from the Proceedings of Bridges journal. It’s a good, quick read if you want to learn more about this odd feature of the Mercator projection.

The paper makes the case that the Mercator projection has many possible applications in digital photography and graphic design. The fractal-like infinite scaling feature can make for some striking digital panoramas. However, the authors acknowledge the reality about the Mercator: it’s not very good for making practical world maps.

Can a map be racist?

The Mercator is not the most popular map projection because it is necessarily the best one. Its popularity is a historical legacy that has persisted since the 16th century, a time when maps were important tools for ocean navigation.

All map projections have strengths and weaknesses. The Mercator is accurate with respect to angles. Lines of constant compass heading appear as straight lines on the map. In other words, if a ship sails in a constant direction according to its compass, Mercator will show its path as a straight line. This feature is not true of all map projections, and it is clearly an important one for navigation. However, it comes with a cost. The Mercator’s biggest shortcoming is its inaccuracy with respect to size. And in this case, size matters.

The problem is not just that the Mercator gives an inaccurate picture of the world, although it does. What makes the Mercator projection particularly controversial is that it makes Europe and the United States look much larger than they really are, giving them more prominence. Likewise, it takes prominence away from Africa, South / Central America, and everywhere in Asia except for Russia.

gall peters map projection
The Gall-Peters projection and the true size of Europe (large version)
mercator equator
Mercator maps are often clipped unevenly, giving the northern hemisphere more prominence (image source: North Dakota Historical Society)

Compare the sizes of Europe and the U.S. under the Mercator projection to their sizes under the Gall-Peters projection. Gall-Peters is an equal area projection, which means the area of each region in the map is preserved accurately. With Gall-Peters, Africa takes center stage and Europe is just a tiny place off on the margin.

In the 1970’s, there was a movement to make Gall-Peters the “standard” map, a less-deceptive alternative to replace Mercator. Though clearly it never caught on.

As with all map projections, Gall-Peters trades accuracy in one property at the expense of distorting other properties. Namely, it is accurate in terms of size, but very inaccurate in terms of shapes. Notice how the countries in the center are tall and elongated whereas those at the top and bottom of the map are flat and wide. Gall-Peters may get the size of Greenland correct, but when viewed from above in real life, Greenland’s true shape is much closer to what the Mercator projection shows.

There is also another point supporting the view that Mercator is culturally biased. Often the top and bottom of the map are clipped unevenly, giving more space to the northern hemisphere and putting Europe and the U.S. closer to the center.

The one shown in this post comes from the North Dakota Historical Society. The equator was added by me to show how far off center it is.

North Korea World Map
World map allegedly found in a North Korean government building

So, is the Mercator map projection racist as some claim?

Clearly the answer is no.

Mercator was created for very practical reasons, not to denigrate a particular race. More importantly, when countries favor policies that promote their own importance and their national interests, that’s called nationalism. And it would be strange indeed to find a country that does not (see, for example, these Pacifc Ocean centered world maps from Japan, China, and North Korea)

That being said, the Mercator projection is still probably not the best choice for a standard world map.

 

Comparing these and other map projections

Mercator and Gall-Peters are two of the most well-known map projections, but there are thousands of others, each with its own strengths and weaknesses according to the purpose for which it is intended.

If you would like to explore some of the possibilities and see what they get right and what they get wrong, give the graphic below a try. Here are some of the other projections it shows.

  • The Miller projection is something of a compromise between Mercator and Gall-Peters. It corrects for some of the size distortion, but does a good job of retaining the correct shapes. It is the projection used for most of the maps on this site.
  • Winkel-Tripel is the projection that National Geographic uses. From a mathematical perspective it may be the most “correct” projection. That is to say, it is the most balanced with respect to the various types of distortion introduced by map projections: area, isotropy (local scaling), flexion (bending), and skewness (lopsidedness).
  • The Mollweide projection is my personal favorite. Like the Winkel-Tripel, its distortion is very balanced, but I prefer Mollweide because of the clean, rounded shape it gives the world.
  • Stereographic projections are the general family of map projections that the Mercator belongs to. The one shown below is constructed in a similar way to Mercator, except in this one, both the North Pole and South Pole are visible.
  • The Eisenlohr and Guyou projections are not particularly common ones, but I added them in to show a bit more of what’s possible

The purple circles overlaid on top of the map are known as Tissot’s indicatrices. They are there to help illustrate how and where each projection distorts the map.

World map projection comparison

Full screen version

For mobile browsers, tap the image below for a full screen graphic comparing these map projections.

map projections

 

More

mercator projection uncropped mapTo see how the Mercator projection distorts certain countries compared to others, have a look at The True Size Of, an interactive map that lets you drag a country around the world map and see how its true size compares to other countries.

The West Wing has a great clip explaining the Mercator vs Gall-Peters controversy.

Also, find out from XKCD what your favorite map projection says about you.

My latest project, Elementus, aims to bring transparency to the cryptocurrency market. Check out our blog for some crypto-related data visualizations.

 

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Max Galka

I'm an NYC-based entrepreneur (my newest project: Blueshift) and adjunct instructor at UPenn. I'm fascinated by data visualization and the ways that data is transforming our understanding of the world. I spend a lot of time with my face buried in Excel, and when I find something interesting I write about it here and also as a Guardian Cities and Huffington Post contributor.
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  • http://www.linkedin.com/profile/view?id=187410430&trk=tab_pro Dr Frank Ashall

    This is an eye-opening, educational and fascinating article. Thank you. There is a lot of junk on the internet and this is NOT part of that junk.

    • http://metrocosm.com Max Galka

      Thank you Frank! Appreciate the kind words.

  • JOhn Mackie
    • http://metrocosm.com Max Galka

      Agree. I like the Robinson projection too. Actually should have included it here.

  • Thomas Johansen

    I have in fact on numerous occasions encountered the argument that the Mercator projection is racist. While one can always argue that such unjust influences initially, to some degree, contributed to its design, the persistent popularity of this particular projection has become a burden to the western people.

    Public opinion regarding global justice has been formed based on inaccurate assumptions about how resources and landmass are distributed among different populations, leading to public support for a distribution at a greater expense of the West than what would have been the case if those assumptions had been closer to reality.

    The West is constituted by a rather modest share of the world’s landmass. It contains natural resources that enable prosperity, which has been realized not by these circumstances alone, but by the merit of the Western people. It has now been decided that all of this should be shared with the rest of the world through a liberal immigration policy that will result in most of the Western world being taken over by foreigners in a few years time.

    Maybe they too have been misled and will be disappointed when they discover that they didn’t conquer as much territory as it first seemed. In any case, the widespread use of the Mercator projection, misleading as it is, has played its role, however big or small, in making this happen.

    • Korakys

      The only aid that the Mercator projection has been to colonialism, is in helping ships more reliably travel to distant shores!

      Mercator stayed popular because it was easy for illustrators and cartographers. Since computers took over the illustration of maps Mercator has been on the decline.

      I shall also note that Greenland, the greatest beneficiary of Mercator size distortion, is the only place where colonialism completely failed – to the benefit of the natives.

      • http://metrocosm.com Max Galka

        A few counterpoints for the sake of debate.

        On your first point, that may be true and probably is. But I think it’s also plausible that Mercator has had a detrimental cultural impact, reinforcing perceptions about European superiority, even if it’s not intentional. I imagine there is plenty of research out there that has looked into the question. Would be interesting to see whether there is a clear answer.

        Mercator is only helpful for navigation if you are traveling along rhumb lines, which as I understand people have not really done since the 1800s, when they started using great circles. What aspects of Mercator have made easy for illustrators and cartographers to allow it to persist for an additional 200 years? The math of the equirectanguar projection would seem to me to be simplest one to work with.

        Funny point about Greenland. Was not aware it even had natives.

        • Korakys

          Yeah, Greenland was settled by Vikings in about 1000CE. They stuck it out for about 400 years, but they were unwilling to do the things the Inuit were doing to survive (as a Kiwi I know all about trying to be more culturally proper than the motherlanders ever are. For us it was Britain, for the Greenlanders it was Norway). Eventually the Greenland Norse all died out, while the Inuit stayed strong. (Jared Diamond’s book _Collapse_ lays out all the info nicely, great book.)

          Nearly all the shoreline of places that were settled were mapped, at least preliminarily, prior to 1800. Once you have a chart, a sextant and a clock other issues take precedence, like the weather, in how easy it is to sail to colonies.

          The point about illustration may be a bit of a stretch, but I was thinking since basically all sub-continental maps are drawn in Mercator (i.e. shape accurate) then you could just take those, scale them appropriately and them stitch them together to create a world map. I must admit I don’t know how survey data is translated to an illustrated map, but it seems to me that maintaining shape uniformity between global and local maps would make things easier in a pre-computer age.

          You say there is probably research out there that has looked into it, but I can’t even imagine how someone would begin to test this. Even in Mercator Europe is still noticeably smaller than Africa and remember that Europe was never united during the main colonial era. I mean, compare the size of Iberia to South America, or Britain to North America, France to West Africa, the Netherlands to Indonesia; could anyone really have imagined that these countries subjugated their colonial possessions because they were bigger on the map! They are plainly not. Imagine the horror of an Indian discovering that Britain is really a twelfth the size of India rather his previously supposed sixth. I doubt it would change his cultural perceptions or beliefs at all.

          It seems to me that the fact that Europe is placed at the top of the map would be a much larger, though still minuscule, effect. Although even as a resident of the most austral nation in the world I still think the northern hemisphere should be on top, after all it contains 3/4s of the land and more than that of the population. Perhaps an actual issue is the much greater density of named features in Europe and other “Western” places than their ex-colonies on most world maps.

          Well, that ended up being longer than expected. I must admit I groaned when I saw you were going to cover this as I have already encountered the topic 2-3 times recently, but as I glanced down the page I saw that you have covered it far better than others. Well done, I do enjoy your map blog.

          • http://metrocosm.com Max Galka

            Having visited Iceland a few times, I am amazed that anyone was able to settle in such an inhospitable place. It says a lot about Greenland if it was too difficult for the Vikings. I really liked Guns, Germs, and Steel. Have been meaning to read Collapse.

            Still have not looked to see if there is any research like that out there, but I imagine there are some creative ways to see if perception of a country’s size (or location / features) impacts people’s opinions about it. It doesn’t have to be specifically about European colonialism, or necessarily give a conclusive result (e.g. are people more willing to support military spending after seeing how scary Mercator makes Russia look?). Agree with your logic and my guess is that you are probably right, but as evidenced by the current election, people’s opinions can be swayed by unpredictable and irrational things.

            Thanks! Appreciate the feedback about the post, and also your willingness to share your thoughts. Intelligent, rational, and friendly debate is very rare on the internet. 🙂

    • http://metrocosm.com Max Galka

      Think you make some good points. There is certainly a plausible argument that Mercator has had a real world impact that unfairly benefitted the West. Though I think there is a very plausible argument that it has not had any impact at all. If I understand, your point is that large perceived physical landmass gives countries an advantage, which should be true whether that perception is real or not.

      Mongolia and Kazakhstan have large landmass. Would you also argue they are better off today than they would be if they were physically smaller?

      Moving off maps for a moment, for a smart, analytical guy, I’m surprised to hear you bring immigration into the picture. Illegal immigration is one thing, but the facts leave 0 doubt that [legal] immigration has an enormous benefit for the U.S. All you have to do is look at who is starting all our big businesses that create jobs, and who is behind all of our scientific advances. Heck, 3 of our 4 Nobel Prizes last year were won by people born outside the U.S.

      • Thomas Johansen

        I didn’t take a stand on whether the West has benefited from the Mercator in the past, but I find it reasonable to think that its designer and early advocates may have considered it to be beneficial to exaggerate the size of the West and to place Europe in the center.

        It doesn’t follow that because every country would benefit from a larger landmass, it would also benefit from having a large perceived landmass. Consider your personal wealth. What will you tell me about it? What story you benefit from telling depends on who I am. I could be a journalist from Forbes, or I could be from the treasury.

        It seems clear to me that the West today would benefit from underestimating its share of the world’s landmass and natural resources. The less one has, the less one has to share, and the less one are (expected to be) morally obliged to share. Right now there is an enormous pressure and democratic support, both from within and from the international community, for the West to share from what it has little of – landmass.

        With the rise of cultural and ethnic identity politics that has emerged from the increasingly plural western societies, we cannot analyze this without taking immigration into account. Western territory has become a battleground for group interests. Germany’s recent acknowledgement of the Armenian genocide caused an uproar among the Turkish population in Germany. Indeed, Germany’s ability to acknowledge this genocide at all is dependent on a sufficiently low Turkish population.

        It was mainly Europe I had in mind with this, whose current demographic changes and its consequences bears little resemblance to high-skilled workforce immigration to the U.S.

      • Korakys

        >”There is certainly a plausible argument that Mercator has had a real world impact that unfairly benefitted the West.”

        Really? By what mechanism could this possibly work? Please don’t say things you don’t believe.

        • http://metrocosm.com Max Galka

          Is it so far fetched to say there is a plausible argument?

          To give just one example, put yourself in the shoes of someone living in British Kenya. Who are you more likely to submit to, a country that looks about the same size as yours? Or one that looks one-quarter the size of yours?

          In that scenario, did Mercator actually make any difference? We can speculate, but without supporting evidence either way, I think the right answer is we don’t know.

          • Korakys

            Did Kenyans even exist before the British arrived and drew their lines on a map? Seems to me that they were a group of a lot of different peoples. Here is a map: https://commons.wikimedia.org/wiki/File:East_Africa_Protectorate_and_Uganda_%281898%29.png Now I can’t really tell what is going on in this map, but it sure doesn’t look like Kenya yet and that was 1898.

          • http://metrocosm.com Max Galka

            Did I say Kenya? What I really meant was “Ukamba”. 🙂

  • Alex Pixley

    I *really* enjoyed this article, but I’m a little puzzled why you didn’t go just a bit further and mention projections like Peirce quincuncial or Gringorten polar.

    • http://metrocosm.com Max Galka

      Thanks! My original plan was to show some of the wackier, esoteric examples like the ones you mention. But as I went about it, I ran into some snags with pieces of the map getting stretched across antimeridians and coming out weird. I’m sure there is an easy solution, but since that part of the post is really just an afterthought, it didn’t seem worth spending the time.

  • Mike Liveright

    Thanks for this and the other maps that I have seen. You may want to point to the TV show The West Wing episode that discusses this general topic. It is at: https://www.youtube.com/watch?v=vVX-PrBRtTY

    • http://metrocosm.com Max Galka

      Thanks Mike. Yes, great clip (mentioned at the very bottom).

      • Mike Liveright

        My-Bad. Great minds and Followers think along the same paths.

  • Luciano Ferrer

    ¿No mention to Dymaxion map?
    I have a leg tattoo based on it 😀 (just america continent)

    BTW, very nice article! thanks a lot

    • http://metrocosm.com Max Galka

      They are great! Ran into some snags transitioning some of the more esoteric projections. Dymaxion maps might make for an interesting post themselves.

  • Iapetus McCool

    Is Mercator really the most common projection today? I don’t think I’ve seen any modern atlas, and very few wall maps that use if. Even my 1918 edition atlas shows other projections first.

  • Bamsiepants

    Excellent enhancement with the addition of the map. Great article.

  • ChicoCDM

    In summary: Africa is one big mess!

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