Map Projections

During this week's lab, we explored the different world map projections offered by ArcMap. Map projections are significant in geography because they allow us to view planet Earth on two-dimensional surface. Although map projections are more important and useful than globes, map projections can be misused and distort the globe at large. No flat map can portray both a conformal projection and an equal area projection. Thus, you are left to choose which projection is best for the task at hand.

In this lab we were left to choose two equal area projections, two equidistant, and two conformal; a total of six different projections. Illustrated below are the projections of my choosing. We were also required to measure the distance (in miles) from Washington D.C., U.S.A. to Kabul, Afghanistan. Immediately we can see some of the perils when dealing with map projections; accuracy of distance measurement. Take for example the equal area projections, the Behrmann Equal Area Cylindrical Projection measure the distance of the two locations at 8,763.0899124 miles. While the Bonne Projection measure the distance of the two locations at 6,715.658553 which is short coming of the later. Thus, if we are to compare distances of places, depending of the projection used, we must either measure all locations in the same projection for accuracy or explain that this measurement may not be accurate. However, in business accuracy is priority. Measurement is only one of the perils visible. Scroll down to the Conformal Projections examples. Notice that both projections are conformal meaning that the projection is shape preserving, but the Krovak Projection displays a globe while the Mercator Projection illustrates the globe as a rectangle. Moreover, the Mercator Projection portrays Antarctica as being a massive land mass than the rest of the continents. Unlike a globe there are visible distortions, nonetheless these projections can be suitable for a specific problem.

 The potentials of projections is that they can provide spatial data at a specific point on the Earth. Unlike a globe, we are able to use a projection to enhance a specific point for the spatial properties. For instance, equidistant projections maintains the shortest distance between any two points. This is visible with the two examples illustrated below, Conic and Cylindrical. Although the measurements of the two examples are different, they maintain less difference than the other projections. Thus, this projection could be useful in desktop mapping software for measuring two points. 

All in all map projections are not only useful to ArcGIS, but also to the public. For instance google maps most likely uses a projection for enhancing street views and locations. Also, sailors use map projections to navigate the sea. Though the projections have known distortions, there are different types to choose from that will properly illustrates your information. We must not be pessimistic about map projections and distortions, instead we as geographers in a technological age should be able to decipher between what is important to the map and what can be distorted.

Please enjoy the various map projections chosen.