Map Projections of the World: Which is the Best?

Map Projections of the World: Which is the Best?

We examine the most common map projections in the world, how they work, and which is the best

Kia is usually described as the geek in our relationship. She's the one with a computer science degree, she's the one with the editor's eye, and she's the Star Trek fan who calls herself Seven of Nine...which is apparently cool? A friend recently described her as “the one who puts the apostrophe in rock ‘n’ roll.”

That said, I have a few streaks of geek in me too. I'm a bit of a history nerd and can talk about camera lenses and filters in great detail. But most of all, I love cards.

One day, perhaps when we win the lottery and can afford a house with more than one bedroom, I will have a cartography room dedicated to my dozens of Ordnance Survey maps, my collection of outdated classroom maps with names like Rhodesia and Bechuanaland (now Zimbabwe and Botswana), and my assortment of massive atlases and creaky globes.

I love how cards spark conversations. Even with a lone map on a flimsy wall in our London apartment, I saw people stop, observe, and ask curious questions like "Why isn't the equator in the middle?" or “Why does Greenland look smaller?”.

The answer lies in the exciting topic of map projections. Let me elaborate on this.

Why do we need map projections?

In a perfect world, the Earth would always be represented as a sphere (more specifically, an oblate spheroid or ellipsoid). However, a globe is not practical. It cannot be easily carried, transported or stored in your bag.

It is not suitable for large-scale use, e.g. B. to find directions in a city or follow a hiking route, where a more detailed picture is essential.

On a curved surface, measuring terrain characteristics is difficult and it is not possible to see large parts of the Earth at once. Globes also don't work well on our smartphones, tablets and computer screens.

alt="Tablet with mapping app">DreamtimeGlobes don't work well on flat screens

The above problems make globes expensive to manufacture, especially in different sizes and scales, and impractical for everyday use. That's why we create maps.

Whether paper form such as leaflets, booklets or atlases or digital formats embedded in websites and applications, we create two-dimensional projections of the spherical earth.

What is a map projection?

In its simplest form, a map projection is the transfer of the curved surface of the Earth (or part of it) onto a flat surface using mathematical equations: making the three-dimensional two-dimensional - or making the curved world flat.

alt="maps-changed-world-Bleau">Public domainFlattening the curved world is the challenge of mapping

During such a transformation, latitude and longitude lines are converted into Cartesian coordinates (x, y), which represent the location of points on a flat map. There must be distortions - they cannot do that. Depending on the purpose of the card, some of these distortions are acceptable and others are not.

A map projection is classified depending on the type of mathematical formula used to project the spherical globe onto the flat map. Map projections preserve some of the sphere's properties at the expense of others, producing maps that appear to represent the world in different ways.

Basic types of map projection

The best way to describe how a map projection works is to imagine a piece of paper (the map) placed over the earth (or a globe) to create the latitude and longitude lines for the map.

Where the piece of paper touches the globe, there is no distortion on the map; it is an exact replica of the globe. However, where the paper is not flat, distortion occurs. The further the paper is from the earth's surface, the greater the distortions.

alt="how distortion works on paper">ICSM: CC 3.0Imagine a piece of paper laid flat on the ground - this will be the map

Mathematics in various projections attempts to overcome this problem - but none eliminates all distortions. Broadly speaking, there are three basic techniques used to create a projection and therefore a map.

Azimuth: This piece of paper is laid flat and touches a globe at one point - usually a pole, but not always.

Conical: The paper is rolled into a cone shape and touches a ball on a circular line. Typically the tip of the cone is positioned over a pole.

Cylindrical: The paper is rolled into a cylinder around the globe, touching the Earth in a circular line - usually at the equator.

alt="Types of Projections">ICSM: CC 3.0The three main types of map projection: azimuthal, conical and cylindrical (lr)

There are also pseudocylindrical ones. This is essentially the same as cylindrical, but with advances in computer modeling it became possible to calculate the longitudes as curves, thereby reducing distortion near the poles. It is also my favorite variety.

alt="Map projections-pseudocylindrical">Strut: CC 2.0Advances in computing mean distortions near the poles are reduced in pseudocylindrical projections

Common map projections

Azimuthal stereography: The oldest form of map projection can be traced back to the 2nd century BC. BC. The oldest known record of this projection is by Ptolemy in 150 AD. Stereographic projection is the most common form of azimuthal projection still in use today.

The appeal of the projection is that the Earth appears as if viewed from space - or a sphere. The shapes of the landmass are generally well preserved, although extreme distortion occurs toward the edge of the map.

alt="two globes">Tobias Jung CC 4.0Looks like a sphere, although there is extreme distortion towards the edge

Mercator: In 1569, Geradus Mercator created the most famous and well-known map projection, which, despite its enormous distortions, is still widely used today.

This is why Greenland looks as big as Africa on Google Maps. There is little distortion near the equator. Distances along the equator are always correct, but nowhere else.

alt="Map Projections-Mercator">Strut: CC 2.0Similar looking? Greenland is the size of Africa on Mercator's map

It became the standard map projection for nautical purposes because of its ability to represent lines of constant true direction - crucial in a time when sailing ships and navigation were based on direction alone!

Take a look at thetruesize.com to get a sense of how the Mercator projection (and Google) distorts our view of the world.

alt="true size of map website">thetruesize.comThis app shows the true size of countries that are misrepresented on Google Maps

Gall stereographic: In 1855, clergyman James Gall presented a map that was intended to resemble Mercator's, but with less distortion of scale and area near the poles. The cylindrical stereographic projection, based on two standard parallels at 45° North and South, went unnoticed when announced.

alt="map projections-gall">Strut: CC 2.0Similar to Mercator but with less distortion near the poles

Gall–Peters: In 1973, filmmaker Arno Peters presented a cylindrical world map based on James Gall's map above. In contrast to the Mercator projection, Africa is shown at its true size: 14 times larger than Greenland.

It is an evolution of Peters’ previous work. Like Gall's map, the map establishes the latitudes 45° north and south as the regions on the map that do not exhibit distortion.

alt="map projections-gall–peters">Strut: CC 2.0Africa is represented at its true size: 14 times larger than Greenland

Lambert Conformal Conic: In 1772, a Franco-German mathematician and scientist named Johann Heinrich Lambert published seven map projections! His Conformal Conic map projection, considered revolutionary at the time and still important today, has become a standard for mapping large areas at small scales in mid-latitudes such as the United States and Europe.

It's not very good for southern latitudes, which usually cut off somewhere around 30° South.

alt="map-projections-Lambert_conformal_conic">Strut: CC 2.0Not useful for South Africa, Australia and Argentina

Robinson: Ahhh, my favorite map projection. I like the Robinson because it is more accurate and more attractive than the Mercator. The map was developed in the 1960s by Arthur H. Robinson, an American geography professor, because modern mapmakers were unhappy with the distortions of the Mercator projection and wanted a world projection that felt more realistic.

Therefore, Robinson projection has become more popular than Mercator projection.

alt="Map Projections-Robinson">Strut: CC 2.0My favorite – the Robinson just looks right

Since it is a pseudocylindrical projection, the standard parallel is at the equator and still has similar distortion problems as the Mercator projection. However, the range of acceptable distortion is expanded from 15° north and south to 45° north and south.

There is also less distortion in the polar regions. Unlike the Mercator, the Robinson has the latitude and longitude lines evenly spaced on the map.

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Literature recommendations:

Prisoners of Geography: Ten Maps That Explain Everything About the WorldAll heads of state are constrained by geography. Your choices are limited by mountains, rivers, seas and concrete. To understand world events, we often focus on people, ideas and political movements, but without geography we never have the full picture.

The Revenge of Geography: What the Map Tells Us About Coming Conflicts and the Battle Against DestinyIn this provocative, surprising book, Robert D. Kaplan, the bestselling author of Monsoons and Balkan Ghosts, offers an insightful new prism through which we can view global upheavals and upheavals to understand what lies ahead for continents and countries around the world.

Main image: javarman/Shutterstock

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