Lab #5

 

     

     In this week’s lab, I got to test out different map projections. Map projections are putting a three dimensional earth on a two dimensional surface. Since there is no perfect representation of the 3D earth, we can only get different types of map projections for different purposes. Like said, all map projections can preserve certain properties and distort others. In this exercise, I get to generate two maps in each of the three major map projections categories: conformal, equidistant, and equal area.

       Conformal maps have its unique set of properties. Conformal maps preserve angles and direction but distorts shape. This meant the angle between any two lines on the sphere must be the same between their projected counterparts on the map and scale at any point must be the same in all directions. Conformal maps are mostly used for local purposes and seldom for world maps since angles can only be preserved to a certain extent, thus shape or area are greatly distorted when the area it trying to represent is too big. In Mercator, we can see that Antarctica is greatly stretched and looks as it got equal landmass as to all the combined continents. In Stereographic, instead of looking like a planar as in Mercator, it’s spherical and it looks like the upper border of Canada can almost touch the upper border of Russia.

        Equidistant projections, as suggested by its name, are maps that preserve distance. Such projection maintains scale along one or more lines, or from one or two points to all other points on the map. That said, we could measure the distance between two points more accurately than the other two projections, conformal and equal area. Equidistant projections are very important in aviation purposes; we would want to know the accurate distance when we are traveling. In comparison, we would travel 2,000 more miles using the Mercator map than if we were using Azimuthal Equidistant! Even though such projection is very effective in preserving distance, it distorts area like conformal projections. As seen in Equidistant Conic, we can see that Antarctica is distorted in such a way that it appears to stretch across the entire bottom globe.

          Finally, equal area projections, the last of the three major projections, preserve area. Equal area maps are especially useful when comparing land area between places. For example, Antarctica looks more appropriate in size in both maps, Eckert VI and Mollweide. Even though it has advantage in maintaining area, it distorts shape. It become evident when we approach the poles; the shape of the poles can be flattened out as in Eckert VI or squeezed in Mollweide. 
            I had a lot of fun exploring different map projections and compare them to each other. This exercise teaches the different purposes of each map projections. Though each map projections have its own special preservative properties, they can also introduce distortion. Thus, I have to be extra careful to figure out what exactly I am looking at and what information I can draw from it. It’s also an important knowledge to have because now I know the usage of each map projections and save it for future references.