'A map projection is a geometric transformation of the earth's spherical or ellipsoidal surface onto a flat map surface' [Kimberling, 2012, p. 57]. The different map projections and their applications were the subject material covered in Module 2 of Communicating GIS. While the intensity and depth of map projections is well beyond the scope of this blog post, a great starting point on this subject is the ESRI documentation regarding coordinate systems; you can find the resource at this link:
Geographic vs Projected Coordinate Systems
Essentially, lab assignment two was applying different projected coordinate systems to various maps and examining how they affected the land masses differently. As the round surface is projected onto a flat surface [developable surface], some integrity will be lost; this will either be in distance, area, angles, or distances [Kimberling, 2012]. Each of the different projection types will preserve some of these qualities while distorting others. It is up to the cartographer to determine which projected coordinate system is appropriate for each case.
The final part of the lab was to pick a state and determine which coordinate system was the best choice to create an accurate map. As shown in the map below, I chose to map the state of Texas. I primarily decided on Texas because a custom projection system was the best option. Two of the most popular projection systems, State Plane and UTM, were not appropriate because the state crosses numerous zones in each of these systems, which would cause major distortion to the map. Conclusively, this map was drawn using the NAD 1983 [2011] Texas Centric Mapping System Lambert projected coordinate system, which is a conformal PCS that preserves the actual geometry of the state.
This lab was very intriguing and informative; the subject of projected coordinate systems is complex and deep, but this module was an excellent introduction to the complexity of this subject.
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