Assignment Five

The three dimensional structure of the Earth has caused significant issues throughout history. Yes, the globe is an applicable tool in order to reference this 3-d structure. However, carrying a globe around is clearly not feasible at all times. When referencing maps, whether that be in hand or on a computer, a two dimensional representation of the Earth is most common. This causes an issue has representing a three dimensional structure on a two dimensional surface leads to distortion in the projected surface of the earth. This assignment allowed us to look at multiple formats by which these two dimension projections are formed and the differences between each format.


Although each projection presents the earth in a different way, they are all useful to us for visualizing the earth. In this assignment, I chose six different projections to look at, each with its own distortion. When looking at Equal Area maps, I chose the Cylindrical Equal Area map and the Mollweide Equal Area Map. Equal Area maps preserve areas of the Earth in the 2-d projection. The Cylindrical Equal Area Map uses a cylinder as a developable surface of the Earth. The Mollweide Equal Area Map specifically decreases angle and shape preservation to increase the accuracy in area representation. As seen in the distances between Kabul, Afghanistan and Washington, D.C., these two map projections of the same larger category have a 3,019 mile difference in what each represents for the total distance of the cities.
For the Equidistant Map Projections, I chose the Equidistant Conic Map and the Sinusoidal Map. Both of these Equidistant Maps preserve distances from a set point. The Equidistant Conic map is a standard equidistant map that uses the cone as the developable surface. The Sinusoidal Map keeps the distances along the parallels of the graticule intact. The differences in distance between the two cities on these maps was 3,051 miles. For the Conformal maps, I used the classic Mercator Projection and the Gall Stereographic Map. Conformal Map Projections preserve the angles in the local spaces of the Earth's surface. Both maps create right angles when meridians intersect parallels. Stereographic maps differ as they keep the shapes of circles preserved. The distance difference between the two Conformal Map Projections I chose was 3,039 miles.

(Information for the previous paragraphs was found from the recommended Wikipedia source for us to look at)


As seen by these projections, not only do different types of map projections differ vastly in the information presented, but even maps of the same category differ as seen by the average difference of around 3,000 miles. Clearly, these projections are not perfect representations of the Earth. Although is the case, these projections are still full on important information for many fields, such as Science, Navigation, Meteorology, and much, much more. The key is to use the specific projection that best suits the focus of one's study, while remembering the information is not exact.