Map projection is the process of converting a three dimensional earth ellipsoid to a two dimensional surface through mathematical conversion. There are many different ways to make a map projection and each one has its own features. To start, the globe is projected onto either a plane, a cylinder, or a cone. All of these surfaces are able to then be unwrapped to take the form of a flat surface. The three main types of projections are conformal, equal area, and equidistant. Each of these map projections preserve a particular property: local shapes, areas, and distances.
While projections make it much easier to view the earth's surface on a flat plane, it does have its disadvantages as well. While some properties might be preserved, others will be greatly skewed. For example, in the mercator projection, while local angles and shapes remain the same, the areas change greatly. This is why when you look at the map, Alaska looks like it's the same size as Brazil.
For this exercise, we were asked to show 6 different projections of the world and map the locations for Washington DC and Kabul, Afghanistan. I made 2 of each type of map projection then used the measuring tool to find the distance in miles between the two locations. After finding all of the distance, I found the map projections can greatly skew long distances on a map. I ended up with a wide range of distances from as high as 10,082 miles to as low as 5,061 miles, a difference of 5,021 miles. The actual distance between the two cities is approximately 6,900 miles. We can see that using map projections can be dangerous when making measurements.
While map projections can seem to not be accurate when dealing with measurements and comparison of values like area and shape, they are still very important. The thing you have to remember about map projections is that it is meant for illustrative purposes. When using these maps, we are concerned with relative locations and not necessarily quantitative values.
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