Week Six Lab

Before this class I assumed that maps were pretty much always the same these days. Before I knew how map projections worked I thought that there was pretty much one standard way to project them so that all maps reflected the same distances and areas and whatnot. I never took into account that the earth is not a perfect sphere and on top of that there are more ways than one to transform a 3D object into 2D. While doing this lab and recording the distances I was astounded at how different some of them were, some have over 1,000 miles of difference.

For this lab the true distance (the no projection map) between Washington D.C. and Kabul is approximately 6,976.426 miles. The projection furthest from the true distance was the conformal Mercator measuring a distance of 10,198.004 miles. This could be accounted for by the fact that the conformal mercator projection maps preserve the angles, distorting distance the most (more specifically over exaggerating the distance). However, the other conformal projection I used (conformal Gall Stereographic) recorded a distance of 7,229.78 miles. This shows that even within the same type of projection type there are differences.

Comparing the equal area and the equidistant projections they both have a variation of a little less than 2,000 miles between the different types within the projection. For the equal area I used the Hammer projection which measured a distance of 8,398.08 miles and the Bonne projection which measured a distance of 6,898.32 miles. In terms of the equidistant projections I used the equidistant Conic (which measured 7,058.30 miles) and equidistant Cylindrical (measuring 5,149.77 miles). The fact that these have a similar difference may be significant, or it might be coincidence.

Map projections can be misleading. Certain projections may be used to manipulate the data being presented. These maps actually look different, they are even shaped differently -- some being rectangular, some shaped like an ellipsoid, etc. Maps are not unbiased or objective, they too are subject to their creators subjectivity and own interests they have in mind. If you want to emphasize the closeness of an area like from the nations capital to Kabul, Afghanistan to show the threat of that area as being closer to home you are not going to use the conformal Mercator projection; instead you would be more likely to use something like the equidistant Cylindrical or equal area Bonne projection. This demonstrates the importance of checking what map projection is used on the map you are looking at.