Lab 3: Exploring Map Projections

Distance (in miles) between Washington, D.C. and Kabul, Afghanistan
Mercator: 10,114.41431 miles
Gall Stereographic: 7,154.417641 miles












Distance (in miles) between Washington, D.C. and Kabul, Afghanistan
Plate Carrée: 10,111.569936 miles
Sinusoidal: 8,094.198608 miles











Distance (in miles) between Washington, D.C. and Kabul, Afghanistan
Bonne: 6,737.656021 miles
Mollweide: 7,924.80534 miles


Map projections are very significant in that they present different views and perceptions of the world in different shapes and forms. In other words, each projection (conformal, equidistant, and equal area) can be seen as a representation of the same idea but from a different point of reference. Different types of map projections have different ways of bringing what is really a three-dimensional spherical object (the Earth) and making it easily readable as a two-dimensional object. Arc Map is very useful when changing, comparing, and analyzing map projections since it permits users to make and activate several layers of data, all under one common projection.

It was by taking part in this lab that I really was able to have a hands-on experience working with the distortions of views and information produced by changes in map projections. Surprisingly enough, the Gall Stereographic conformal and Plate Carree equidistant map projections represented the 2D map of the world in very similar ways especially when it came to the size of the continents. It also surprised me how such an unrealistic heart-shaped view of the world as seen in a Bonne projection (an equal area projection) is not too different when compared to another equal area projection known as the Mollweide projection when measuring the distance between the two cities of Washington D.C. and Kabul, Afghanistan; just a difference of 1187.15 miles. One other very important observation was that between the conformal projections, Gall Stereographic and Mercator, there was a much greater difference in distance (than the one seen between the two equal area projections above) between Washington D.C. and Kabul, Afghanistan—2959.99 miles.

There was great distortion in the relative sizes of the continents when they were accurately represented in different projections. Out of all of the map projections observed in the lab, I found that the equidistant Sinosoidal map projection was the most distorted and most different from all of the rest. It seemed to me that North America and Asia were stretched vertically in a very exaggerated manner.

Some of the perils of map projections based on this exercise were found while measuring the distances between Washington D.C. and Kabul, Afghanistan. The problem was that I was constantly making the mistake of measuring in meters rather than miles because the measurement tool tended to automatically change back to meters. I had to go back and check each map projection in order to make sure it was measuring in miles to avoid inaccuracies. In the end, I found that the process of separating the different projection layers and making separate files for them in order to post them on my blog was a little tedious; especially when I realized that each map needed its own scale bar even though it shared the same type of projection with another map. Example: Even though Mercator and the Gall Stereographic were both conformal map projections, I needed to give each one of them a separate scale bar.