How do Map Projections Work?

Summary

This video script delves into the fascinating world of map projections, explaining how they attempt to represent the globe on a flat surface with varying degrees of accuracy. It highlights the Mercator projection's historical significance and its distortion issues, particularly near the poles. The script then introduces the Robinson projection as a more accurate alternative and explores various other projections, each with unique visual representations and mathematical principles. The video emphasizes the impossibility of perfect map projections and the ongoing quest for the most accurate depiction of our spherical Earth on a flat plane.

Takeaways

• 🌍 Maps are attempts to represent the Earth on a flat surface, but this is impossible to do without distortion due to the transformation from a sphere to a plane.
• 📏 The Mercator projection, invented in 1569, was widely used for navigation as it represented constant bearing courses as straight lines, but it distorts the size of objects away from the equator.
• 🧩 The Robinson projection, developed in 1987, is known for its minimal size distortion and is now commonly used by the National Geographic Society.
• 🔍 Different map projections are created to preserve certain properties of the Earth's surface at the expense of others, depending on the map's intended use.
• 📚 There are hundreds of map projections, virtually infinite, as they can be adjusted or created anew to suit specific purposes or to minimize certain distortions.
• 🌐 The Behrman projection, from 1910, is an example of a projection that, while symmetrical in distortion, disproportionately represents the sizes of continents.
• 🛫 Lambert's conformal conic projection, from 1772, is still the basis for many aeronautical charts because it approximates great circle routes for flight distances.
• 🌐 The stereographic projection, dating back to antiquity, was used to depict the northern hemisphere with high accuracy, despite increasing distortion away from the center.
• 🔬 The airy minimum error projection aimed to depict all continents with minimal error by splitting the globe and representing it in two circles.
• 🦋 The Cahill conformal butterfly projection, inspired by Leonardo da Vinci's ideas, divides the globe into eight triangles, providing an accurate depiction of sizes and shapes.
• 🌐 The Dymaxion map, from 1943, transforms the sphere into an icosahedron and flattens it, preserving shapes and sizes but resulting in heavy interruptions.

Q & A

What is a map projection according to the Wikipedia definition?

A map projection is a way to flatten a globe's surface into a plane in order to make a map, but it's impossible to do it in a way that is 100% accurate due to the transformation of latitude and longitude lines from the globe into locations on a plane surface.

Why is it impossible to create a completely accurate map projection?

It's impossible because when transforming a three-dimensional sphere onto a two-dimensional plane, some distortion is inevitable to represent all the geographic features accurately.

What is the most well-known map projection used globally?

The most well-known map projection is the Mercator projection, which was presented by Flemish geographer and cartographer Gerardus Mercator in 1569.

What was the primary purpose of the Mercator projection when it was created?

The Mercator projection was created to represent any constant course of constant bearing of a ship as a straight segment on the map, making it ideal for navigation during the times of European colonialism and maritime discoveries.

What is the main issue with the Mercator projection?

The main issue with the Mercator projection is that it inflates the sizes of objects away from the equator, causing significant distortion towards the poles, making countries and continents appear larger than they actually are.

What is the Robinson projection and why is it favored over the Mercator projection?

The Robinson projection, developed in 1987, is favored because it almost entirely solves the size distortion issue present in the Mercator projection, making it more accurate for representing the world's continents and countries.

Why are there so many different map projections?

There are many map projections because depending on the purpose of the map, some distortions are acceptable while others are not. Different projections are created to preserve certain properties of the earth at the expense of others being distorted.

What is the Behrman projection and how does it distort the map?

The Behrman projection from 1910 is an example of a projection that shows Central America, South America, and Africa disproportionately large compared to North America, Europe, and most of Asia, but in a horizontally symmetric way from the equator line.

How does the transverse Mercator projection differ from the standard Mercator projection?

The transverse Mercator projection stems from the Mercator projection but is depicted in a different shape/angle. It has less distortion at the poles but other areas suffer as a consequence, such as Southeast Asia and South America appearing too large.

What is the significance of the Lambert conformal conic projection?

The Lambert conformal conic projection from 1772 is significant because it is extremely proportionate in almost every aspect, and it is still the basis for many aeronautical charts used by air pilots due to its ability to approximate great circle routes for flight distances.

What is the Dymaxion map projection and how does it attempt to represent the world?

The Dymaxion map projection from 1943 attempts to transform the sphere into an icosahedron, a shape with 20 sides, and then flatten out those sides on a surface. It preserves shapes and sizes well but is heavily interrupted, indicating that its goal was to create an accurate depiction rather than a practical navigational tool.

Why are some map projections not suitable for practical navigation?

Some map projections are not suitable for practical navigation because they prioritize accuracy in certain aspects over the ease of use for navigation. For example, the Dymaxion projection is more about creating an accurate flat representation of the globe rather than facilitating navigation.