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Understanding map projections

A quick reference guide to one of the most important aspects of cartography

May 26, 2015

Few subjects are so controversial – or at least, misunderstood- in cartography as map projections, especially if you’re taking your first steps in this field. And that’s simply because every flat map misrepresents the surface of the Earth in some way. So, in this matter, your work in map-mapping is basically to choose the best projection that suits your needs and reduces the distortion of the most important features you are trying to show/highlight.

But it’s not because you don’t have enough literature about it. There are actually a bunch of great resources and articles that will help you choose the correct projection for your map, so we decided to bring together a quick reference list.

Hope you enjoy it!

Let’s start with the obvious one: The Wikipedia list of map projections, where you’ll find a table with an overview of significant map projections, including those described by specific articles in Wikipedia. You should also read the main article about map projection.

Partial screen capture of the website Wikipedia
(image: Wikipedia)

Another interesting overview of available map projections is available at the U.S. Geological Survey’s website. This page includes not only a visualization of the main types of projections, but also when they’re suitable for use.

Partial screen capture of the website USGS map projection
(image: USGS)

In our coverage of Malofiej 23, we shared the video mentioned by National Geographic’s Martin Gamache during his presentation. When talking about projections, Martin showed one of the works (the “Beneath the Oceans” supplement map in the September 2012 issue of the magazine), where the team decided to use an interrupted Mollweide projection centered on the Pacific, to show each ocean as a whole with the least possible distortion. Since this projection is not as common as, for example, Mercator, they also produced this video explainer that helped readers to explore it.

Ben Jones wrote this article on Tableau’s blog about the topic, and Maps Mania’s Keir Clarke pointed us to the Eight Projections project – a series of maps of regions of the world drawn in eight different map projections. All eight projections are displayed on the same map at the same scale and with the same center, so this is an excellent way to visualize the differences.

Partial screen capture of the website Eight Projections
(Eight Projections)

As for a more humorous approach, we shared last year here on Visualoop this image found on Joe Hanson’s excellent It’s okay to be smart.

Map projections as human heads

And to close…XKCD.

map_projections

 

Hope you find these references useful, although this is far from being an exhaustive list – more like a starting point. If you go deeper in your research about map projections, and have any interestiung links to add, just let us know on Twitter (@visualoop).

And if you want to stay up to date with the latest interactive maps don’t miss our weekly round up, published every Wednesday – we also have this Pinterest board, with thousands of examples.

Written by Tiago Veloso

Tiago Veloso is the founder and editor of Visualoop and Visualoop Brasil . He is Portuguese, currently based in Bonito, Brazil.

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