In this laboratory, we had the opportunity to create map projections using ArcMap. Utilizing an existing data set, we were able to create maps of the world that featured different types of projections, primarily conformal, equal area, and equidistant. To further explore the variations in the maps, we also investigated that respective distance between Washington D.C. and Kabul, Afghanistan as determined by the projections. Below are the projections created in the lab:
The map projections above demonstrate the process of converting the three-dimensional world into a two-dimensional map. This transformation takes the spherical coordinates of the earth and projects them onto planar coordinates. The most developable planar surfaces for these projections are a plane, cone, and cylinder. While there are several types of map projections, the three most significant are the conformal, equal area, and equidistant. A conformal projection, shown in the first map, preserves the shapes and angles on the map. The second map shows an equal area projection which conserves the proportionality of areas on the map as they are in the real world. Finally, the third map, an equidistant projection, shows a map whose distances from the center are equal. These three map types each possess valuable benefits, but they also exhibit significant flaws.
The conformal, equal area, and equidistant map projections all offer substantial advantages. For example, because the conformal map projections conserve angular separation, they are optimal for flight usage. As shown on the two Mercator conformal map projections, the distance between Washington D.C. and Kabul, according to the projection, is about 10,000 miles. While this value is not necessarily the quoted number (sites such as trueknowledge.com and blurtit.com state the distance is approximately 6900 miles), the two values found for the two conformal maps are the most consistent of any of the other groupings. In addition, the equal area map projection accurately reflects the proportional size of the regions of the world. Both the cylindrical and sinusoidal projections show the comparitive landmass size as would be expected, in contrast to the conformal projections that show the monstrosity of Antarctica. This proportionality would be useful for determining population density or the effect of a continuous phenomenon over large areas. Furthermore, the equidistant map projections are beneficial as they show the relative distance from the focal point of the map. While both the conical and cylindrical projections do not necessarily share the same center, they do standardize distance on the map.
Although these projections offer significant insight into different features of the globe, they also have important faults. Though this analysis is aware that the shown maps are indeed projections, if a reader were to approach them as exact replicas of the orientation of the world, he would seriously comprimise his geographical understanding. For example, if one compares the conformal, equal area, and equidistant projections, he notices that they all distort the presentation of the globe in some form. If an individual took this distortion as truth, he would have a terrible sense of the global picture and may try to combine the features of each map rather than address them separately. In addition, the projections, although they all depict the world, do not project distance consistently. Looking at the maps above, the reported distance from Washington D.C. to Kabul varies from about 7000 miles to 10,000 miles. This shows that there is not only one way to measure distance and that measuremets should be made according to the purpose of the investigation.
Map projections offer crucial understanding into the spatial organization of our world. Although they possess some flaws, they also motivate critical thinking and analysis of the globe. Map projections offer the ability to compare specific attributes of the earth, and allow for detailed analysis of a particular interest. Map projections have the potential to greatly increase a person's knowledge about their environment and for him to assess his position in the world on various levels.
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