The two conformal projections shown here are Mercator and Stereographic projection. For Mercator projection, local areas are accurately displayed and clearly defined. The lines of latitude and the meridians are all parallel, but the lines of latitude become farther apart towards the pole. Therefore Mercator projection cannot show the the poles. Base on the observations made above, Mercator projection is useful for sea bearing or air traveling, but not for navigating in the poles. On the other hand, Stereographic projection is viewed from a point on earth to the opposite point of tangency. Using this method, direction is accurate from the center, and local angles are accurate everywhere. One limitation of this projection is that when both hemispheres are displayed, the shape are very badly distorted. This method of projection is therefore useful mostly when measuring circular areas. As we can tell from the measurement, the distance between Washington D.C. and Kabul for both of these conformal projections are similar. We can conclude that Mercator and Stereographic projections do not reserve distance since the distance between two cities according to GCS WGS 1984 is about 6934 miles.
The two equal-area projections shown here are Cylindrical equal area projection and Behrmann Equal Area Cylindrical. These two are very similar in its shape and form. Both of them have more distortions towards the two poles where distortion is minimized near the standard parallels. The area in these maps are reserved where the direction and distance are slightly distorted. The distance between Washington D.C. and Kabul differs for the two projections because one is slightly narrower than the other one. Apparently equal area projection also does not maintain distance. This method of projection can only be used for world map projection, which gives it a lot of limitations. However, it does a good job maintaining local areas on a world map.
The two equal distance projections shown here are Azimuthal equidistance projection and equidistance cylindrical. For Azimuthal equidistance projection, both distance and direction are accurately depicted from the central point. Although distance are accurate from the center outward, shapes are distorted more as they become farther out from the center. Therefore it is usually used within 90 degrees from the center. On the other hand, the equidistance cylindrical is a grid of equal rectangles. It is very easy to create, but there are small distortions away from the central parallels. Therefore it is usually used for small areas instead of world map. The distance between Washington D.C. and Kabul reflected on these two projections are similar. We can conclude that distance is maintained in a equidistance projection.
From this lab, I learned how useful map projections is when studying this enormous earth. By transforming all the data on a single sheet, we can get a lot of useful information about the distance, area, and direction of a certain region or the entire earth. Working on this lab helped me gain my experience of interacting with different types of projection and learn about the power and limitations of each one of them. Because of the fact that people use these map projections for different purposes, there are a variety of method to choose from when projecting a map. Although very useful and helpful most of the time, map projection has pitfalls as well. It is well known that earth is not flat. Indeed it is a three dimensional sphere-like shape, and all the area reflected on the maps are on the surface of the earth. Therefore it is very hard to transform this 3-D object onto a flat sheet of paper. Thus resulted in distortions in many of the projections. Some of them might maintain the perfect shape, but is not very accurate in distance. There isn't any projection that maps the earth accurately in every aspect. For our purposes, these imperfect projections are enough for us to study from. Overall, map projection is a great tool for us to use while analyzing geogrphic data.
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