MG - Map Projections: From 3D to 2D [LESSON]

Map Projections: From 3D to 2D

In this lesson, we'll start to dive into the world of globe skills, the counterpart to map skills. By the end of these lessons, you'll be able to differentiate between the two and understand the unique advantages and applications of using globes in geography. It is important to note that much of the knowledge and many of the skills you learn in map skills and globe skills are equally applicable to both maps and globes. So, whether you're a budding explorer or just curious about the world, the knowledge gained here will be essential for your journey. Let's set sail into the fascinating realm of globe skills! Exploring and sailing are the perfect metaphors for this module, since many of the first maps and globes were designed with explorers and sailors squarely in mind. Speaking of squares... why are so many maps rectangular when the Earth is a spheroid? 

Guide Point 🧭

Map Projections & Distortion

A globe is a spherical (3-D) model of the Earth that accurately represents its shape, size, and spatial relationships. So, why is the first part of the lesson in “globe skills” about more maps!? Maps and globes are two powerful tools for exploring the world, and both have their unique advantages and limitations. While globes are very useful in representing the Earth exactly the way it is, as an imperfect sphere (sorry, not sorry flat Earthers), or spheroid (slightly imperfect sphere), globes are not easily portable or detailed. After all, a map can show a very small portion of the Earth, while a globe, by nature shows the entire Earth. OK, so easy solution, right? Just show the Earth on a piece of paper. But how can a sphere be accurately represented in two dimensions? The short answer... it cannot. At least not without distortion. Distortion is the alteration or misrepresentation of the size, shape, or distances of features on a map due to the use of a map projection. In other words, all maps, every single one you’ve ever looked at, are wrong. Now, before you start a riot about all the inaccuracies of maps you’ve looked at over the years, let’s put that into different words. Maps don’t exactly, accurately represent the Earth. Maps “project” the spherical Earth onto two dimensions for our use. And depending on the use, the map projection will be different.

Understanding how maps work, including map projections and the concept of distortion, is crucial for anyone studying geography. Map projections are methods used to represent the Earth's curved surface on a flat map, allowing us to navigate and gather information efficiently. However, they come with a trade-off... distortion. As we explore this topic, you will discover how map projections work, why they are necessary, and the various ways they can affect the accuracy of geographical information.

Imagine trying to peel an orange and then flatten the peel on a table. The orange peel is like the Earth's surface, curved and three-dimensional. When you press it flat, you'll notice that some parts stretch, some compress, and others might tear. Map projections are like different methods for 'flattening' the Earth, and they determine how these distortions occur. Some popular map projections are the Mercator, Robinson, and Goode's Homolosine projections, each with its specific uses. You saw this Mercator projection in a previous lesson. You can see it again, below. A Mercator projection, developed by Gerardus Mercator in 1569 is extremely useful for directions. Just ask Google. They, and other popular mapping apps, use it to help people find their way every day. However, it is terrible... and I mean terrible about size distortion. In other words, it makes things appear much larger than they are in reality the further from the Equator they are and much smaller than they are in reality the closer to the Equator they are. By having lines of latitude and longitude intersect at 90° angles, those places where lines of longitude are close together (near the poles) needed to be “stretched out.” But the goal of the Mercator projection was not the accuracy of size, shape, or even distance really, the goal was, and still is accurate directions. Other projections, like the Robinson for instance attempt to balance size and shape distortion in a way that most accurately projects the 3-D Earth, but even it is still "wrong." 

Understanding map projections and distortion will not only improve your map-reading skills but also allow you to critically analyze maps and globes. These concepts lay the foundation for comparing maps to globes and comprehending why both are valuable tools in the world of geography.

True or False: Maps are simple, completely accurate two-dimensional representations of 3-D Earth? click to reveal answer

 FALSE

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