Greetings and hello!
This week we are looking at the effects of different projection methods and systems on map making. First, for those without a GIS background, what is a projection? A projection is a method for transforming the spherical earth into a flat or two-dimensional map. Different projections have different purposes in that they are designed to maintain some aspect of the earth. These aspects include accurate distances, angles, shapes, or areas. Most projections focus on one or two of these aspects, but when talking about multiple, there are usually smaller distortions in all aspects.
The overall purpose of this weeks lab was to look at these distortions through different example projections, apply common coordinate systems, and experiment with different projection options. This culminated in creating the Grid & Graticule map below. I utilized Nevada based on where I am currently living. Using it as a study area, I found a Nevada specific projection when encompasses the entirety of the state.
Interestingly, Nevada has its own projection, called the Nevada State Reference System (NSRS) of 2007. This is a UTM projection and aligns with UTM Zone 12N because the East – West boundary lines of Nevada correspond with that UTM Zone.This is a better choice than the State Plane system because Nevada has 3 State Plane Zones. They are the East, West, and Central zones. For a full state presentation as seen below, UTM Zone 12N is appropriate. There are two datum options that could be utilized however. The NSRS is as of 2007, but there is a UTM 12N with NAD 1983 or 2011 options. I elected to go with the state-specific option for the subsequent map.
Note the multitude of intersecting lines in this map. What are they? The blue lines represent the Projected Coordinate System and are displayed as a "measured grid." That is a grid that shows measurements on the map based on the values associated with the coordiante system. In this case they are in Meters to go along with the UTM zone. The tan lines on the other hand are for the Geographic Coordinates, and represent a 1 degree interval and are referenced in terms of latitude and longitude.
While this was a specific application of a projection and grid/graticule, the rest of this lab looked at everything from different whole world presentations to regional specifics. While this hasnt been the first of my GIS classes to look at projections I think this has been the most indepth manipulation and the best overall understanding of how to use them. For that, its an invaluable lab.
v/r
Brandon
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