Intro to GIS: Week 5 – Projections Part

   This week, and next, the lab exercise examines the characteristics of map projections. The purpose of this lab is to examine (both visually and numerically) a geographic area (in this instance, Florida) transformed by three different projections. To help understand how data is altered by a particular projection, area information for select regions are compared. The result of this exercise is a map that displays the state of Florida in three different projections and includes comparative data for the areas of select counties.

     Three projections are used in this exercise. Albers Conical Equal Area is the native projection of the original shapefile. Universal Transverse Mercator and State Plane North are the other projections used for comparison. I learned how to use the Project tool to alter the projection coordinate system of a layer and also how to select a geographic transformation to go from one geographic coordinate system to another. The lab also reinforces how to select features (by way of the attribute table) and generate a new shapefile from those selections. Below you can see the map I produced for this exercise. The description of the map follows the map image. 

A map displaying Florida as it appears in three different projections.
Areas of select counties are summarized in a table to aid in
understanding how a particular projection alters data.

     My map shows the state of Florida in three different projections. Each map has the same counties highlighted – Alachua, Escambia, Miami-Dade, and Polk. A table of comparative areas is provided to show how data is altered by a given projection. I used a gradient fill for the main background to help create a proper figure-ground relationship. This helps to highlight the three maps of Florida. To maintain a design balance, gradients are also used in the Florida maps and accompanying table. I used blues, yellows, and tan to create a color theme and unify the visual input. I chose to use a single legend as I thought this would keep the map from becoming cluttered. I represented each county with unique color values through a color ramp. The lightest shade of blue corresponds to the county with the smallest area (as noted in the table) and as the blues become darker the areas represented become larger. I chose not to include area information within the legend as I would have had to include a different legend for each map and again, I wanted to keep it simplistic. This is ultimately an esthetic choice since some map users may find the map table off putting and prefer multiple legends.