Coordinate Projection System


The area of interest in my home state of California. California is special because it is the only state that has 6 state plane zones divided within the NAD 1983 State Planar Zone. Most state planar divisions in the United States are divided vertically, but California is vertically shaped, necessitating that it be divided horizontally instead. On the other hand, if we used a UTM projection the zonation for projecting CA would be divided into only two ungainly pieces. Within California’s state planar zone, Placer county falls under Zone 2. 

What are Projections? 

 In GIS, there are different projections a map can be displayed that can present different data from a different view around the Earth. In the Mercator projection, the linear scale is equal in all directions around any point, thus preserving the angles and the shape of smaller objects. The distortion in the size of the object increases as the latitude increases from the equator to the poles.


Mercator is a cylindrical conformal projection, meaning the shape is preserved within small areas, with more extreme distortions near the poles. Closer to the equator, the map features retain better shape and area preservation. 


 


Robinson is a pseudo cylindrical projection that focuses on capturing the entire world map in a pleasing (but not necessarily accurate) format. This is accomplished by adjusting the horizontal parallels and curving meridians until the map visually fits the expected view of the world map. This is a common projection for displaying the world map in a general, public setting. 



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