Week 6: Map Projections

    Map projections exist because of the unavoidable distortions when trying to put the three dimensional world onto a two-dimensional surface. Different kinds of map projections perserve different features of the Earth and therefore serve different purposes. In this lab, we learned to deal with conformal, equal-area and equal distant projections. When measuring the distance between two cities: Washington DC and Kabul, the significance and pitfalls of different projections can be seen.

     One of the most important uses of a map is navigation. If one wants to use a two dimensional map for navigation, the best choice is then probably a conformal map, since local  angles are preserved. However, from the two conformal maps I have chosen for this lab, it is easy to see that there is significant difference. Mercator is clearly more useful as a world map than stereographic since the stereographic projection usually just projects one hemisphere. The two representations of a sphere onto a piece of paper give the viewer different sense of the world. This, again, shows the "art of a geographer": representing the world in the way you want to to affect people's perception of the world.

     One pitfall of using different map projections is that when measuring distances, different projections give different answers. Although the two projections, equidistant conic and equidistant cylindrical projections both suggest that they perserve the distance characteristic of the world, the distance between Washington DC and Kabul is still significantly different. One may be confused by this without taking a GIS class. The equidistant projections preserves the proportional difference in distance: it does not mean the the distances one measures from two equidistant projections are the same. Without an understanding, a map viewer may be confused. 

    Another pitfall of map projections is also linked to the "art of a geographer". A map maker could "manipulate" people's thoughts by representing the world in different ways using different map projections. As the video we have seen in lecture suggests, some maps lead to the false perception that certain countries are smaller than others when they are actually the same size. As said in the video "Why are We Changing Maps"shown in lecture, the lady pointed out that the traditional Mercator projection has "fostered European imperialist attitudes for centuries and created ethnic bias against the third world". This has significant implications on social equality and is something that politicians and policy makers should be educated on.