ArcGIS Map Projections

Map projections are amazing things, as they help us take our three dimensional world that we live in, and turn it into a two dimensional world that we can take in our pockets. There are many different map projections, and everyone has pros and cons to it. For example, we can first look at conformal map projections. They preserve shapes and angles to places. When we use this projection, we can get a sense of where we are going, but the further away from the equator we use this map, we can see just how inaccurate this can be. It does help locate ourselves in the world, but does not preserve area or distances that well. When we take a look at how far it is between Kabul and Washington D.C. we can see that both the Mercator and Gall Stereographic projections estimate the distance at somewhere ovr 10,000 miles when it should be closer to something like 7,000 miles. We see just how bad these maps can be, yet they give us a very familiar representation of the globe.

Next we look at Equal Area projections, which as the name suggests represents equal area. As we can see from the photos, tends to squish the globe a little bit. It is good for keeping consistent area throughout the globe, and this may be useful to determine the amount of rainforest that was burned down or logged. These maps would be useful to map out and accurately measure area on the globe, however, they do not keep distance as well as they should. I chose to represent the sinusoidal and Hammer projections and the distance recorded from Kabul to Washington D.C. happens to be represented as just over 8,000 miles and just over 12,000 miles respectively. The only reason that the sinusoidal projection is close to the magical 7,000 miles is that it is also equidistant, which makes this map useful in more than one way. We can see that these maps do have a use, but representing distances is not one of them.

Our final map projection we look at is Equidistant, and as it sounds it represents distances from a centralized point as the same. The two projections that I chose are the Cylindrical and Conical projections. We first look and notice that the cylindrical projection tends to squish the globe, but maintains the equidistant relationship from a centralized point. As we look at the conical map projection, we see that the distance from a centralized point is pretty equal. These maps are the best for calculating distances, which turn out to represent the distance between Kabul and Washington D.C. as 5,000 miles for the cylindrical projection and 7,000 miles for the conical projection. Looking at the true distance between those two cities, we can note just how close that the conical projection came. As predicted, it did not distort the distance between those two cities too much.

These map projections have a lot of potential because if one wanted to misguide a community by just looking at a map, they could choose a projection in which their point of view is greatly exaggerated and raise concern for their point. Most of the time we accept the map for how it looks, without question, and this is where we could get into trouble. If one were to use a Mercator projection to look at farmland, and noticed that there was not too much compared to what was set aside for development, they might have to figure into account that the farther away from the equator you get, the greater the area distortion is. This can either be used for good or evil, as it can stir certain people into accepting certain facts, but one must be careful to note what they are doing with representing the information that they were given.