Map projections are used to represent the three-dimensional earth on a two-dimensional picture. Just by hearing that statement alone would suggest that there are many implications when making map projections and many maps are distorted. This is because it is so difficult to create a flat projection of an object that is a sphere. Therefore, when you look at different map projections and compare it to an image of the earht, the size and shape of a continent of country on the projection will look different than the continents or countries on the earth. There are many different map projections and each of them have their own unique way of representing the earth. There are three types of map projections: equal area, equidistant, and conformal.
Equal area map projections try to preserve area. This means that the area on the map is proportional to that of the area on the globe. The two examples I have are the Sinusoidal Projection and the Bonne Projection. When comparing the distances between Wathington D.C. and Kabul, Afghanistan the Sinusoidal map distance is 7,800 miles and the Bonne map distance is 6,500 miles. This is obviously because if you look at the projections, the Bonne map is more compact in the north than the sinusoidal. The advantages of using these maps is that it preserves the total area of the country, however the problem is that it does not preserve the shape. Therefore the map is generally distorted because some countries that are far from the prime meridian are not the same thing. It is therefore difficult to generate a true distance between two points because one point is not really in the same place relative to the other.
Equidistant map projections preserves distance from some standard point or line. My two examples are conic and cylindrical. In the conic equidistant map, you can see that that the shortest distance between D.C. and Kabul is over the Arctic in stead of an arch. Therefore the distance in miles is only 6,750 because the path that is taken is different than on other maps. However, the distance between D.C. and Kabul in the cylindrical equidistant map is only 4,900 miles and that is because when the parallels and meridians are proportional, it squishes the lateral distance of the map and makes the map look taller. Therefore, the problems with using there maps is that the farther away you go from the prime meridian and the equator the more distorted the map gets (exception: conic). I believe that the conic example however is pretty accurate because it shows the shortest distance between the two points. However I believe the cylindrical is not accurate in this case because it is completely distorted. If you look at Antarctica, it is not that huge on the globe.
Conformal maps preserve the angles of the intersections of parallels and meridians. My two examples are the Mercator and the Gall Stereographic map. The Mercator map projection distance from D.C. to Kabul is 6,700 miles and the Gall Stereographic is 6,900 miles. These two maps have the closest distance related to one another in my map projection categories. Although they may seem accurate, they may not be. This is because looking at both you will notice that the Mercator is very long but thin and Antarctica is HUGE and take up the entire bottom of the map. The same is for the Gall Stereographic map. Greenland is also not that same size and Australia looks tiny. Therefore, the areas and shapes of objects and distances between them become more distorted the further away from the Equator and prime meridian you go.
From doing this assignment I've learned that map projections can be very deceiving because it is so difficult to get a 3-D figure on a 2-D plane. Most of the projections can only focus on preserving on thing and at that expense, it will distort another. But what projection should we use if they all don't see very accurate. Luckily today we have satellites for GPS and have ways to figure out the true distance from one place to another. However, from looking at all the different map projections, what is the true distance from Washington D.C. to Kabul, Afghanistan?
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