Map Projections: The Real Deal

Maps are used by millions of people on a daily basis. It is easy, however, to take for granted what, exactly, the map user is looking at. The earth is a 3-Dimensional sphere, but maps, on the other hand, depict it in a planar 2-Dimensional format. A globe is not convenient to carry in ones pocket, and thus the map projection is necessary. The process of transposing a 3-Dimensional object onto a 2-Dimensional plane, nevertheless, comes with a fair share inaccuracies. Primitive map projections came with shining a light from the inside of a globe onto a wall, then tracing the features, thus creating a flat usable surface. Problems quickly arose, when obvious distortions in distances and shapes became prevalent. Efforts to preserve different aspects of globes such as distances, shapes, scale, and area gave birth to different mathematically based projections such as equal area, equidistant, and conformal map projections.

The GCS WGS 1984 and Mercator are both examples of conformal map projections. Conformal map projections preserve local angles. For example, a standard conformal map will have the equator in the middle. The further north and south towards the poles, however, the angles are not preserved and distortion is created, often increasing the size of land masses near the poles. The Conic and Sinusoidal maps are equidistant projections. Equidistant projections preserve distance from a standard point or line. Equidistant maps do not come in flat surfaces and are not ideal for daily use. They are used in finding accurate distances because there is little to no distortion at the polar regions. The final map projection used in these exercises are equal area map projections. The Mollweide and Hammer equal area projections satisfy the preservation of area on a 2-Dimensional surface.

No map projection is perfect. Each projection focuses on a specific aspect, but leaves other aspects immensely inaccurate. In general, Mercator projections are among the most common with user-centric programs such as Google Maps. Even though distortions are prominent at the poles, conformal projections are ideal for plotting routes and viewing land masses for directional purposes. Other map projections, such as equidistant maps are not necessarily visually friendly, but are ideal for plotting the actual distance or finding the shortest distance for navigation.

This exercise is perfect for examining the different types of map projections and what differentiates them. The dichotomy between conformal, equidistant, and equal area maps is necessary to understand. Understanding the key uses is equally as crucial. The general knowledge of depicting what projection is best to reference if asked to accurately determine the distance between two objects. In this case, a conformal map would not be best. Furthermore if, asked to evaluate the actual area of a continent near a polar region, a conformal would again not be they key to success. With this base knowledge of map projections, and a greater understanding of map projections are the next steps in truly adjusting to geographic information systems.