Sunday, February 8, 2015

Week 5 - Georeferencing & Projections Part I

This week learned how to change map projections in ArcMap using the 'Project' tool. The above map shows the state of Florida in three different projections, Albers, UTM and State Plane. There are four counties selected on each map, their surface area is listed to easily compare the differences and surface area distortions between these projections.

I created two new data files, each one containing the shapefile of Florida counties in a different projection.  I changed the projections using the 'Project' tool. Then I inserted those new data files into new data frames, which (the data frames) took on the same projection as the first layer in the frame. Then I added an 'Area' column and calculated geometry for that field, getting the surface area of each county. After that I could select the four counties needed for the exercise, create a new layer out of this selection, and use the Symbology tab assign them a color gradient from smallest to largest.

After repeating the surface area addition to the attribute table for each of the maps, I made the map my own. Each map needed its own legend, and items within a layer (specific counties) had to be renamed in the Symbology tab. Last step was to make sure that all the maps are in the same scale and add a common scale bar.

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