It's hard to believe it, but it is already time for the final project. As with any final, we were required to utilize all the skills we've covered throughout the semester in the completion of the project. The project entailed creating a map displaying two thematic data sets over one geographic area along with creating a map with visual hierarchy and proper cartographic design principles in use. There were two options to choose from for the final project, the first option was to map provided data on mean SAT scores and participation percentages in the United States for the year 2014, and the second option was to find our own data and topic of mapping. I chose to use the provided data and create a map depicting the SAT data compiled by The College Board.
In order to display the two data sets, mean composite score and participation percentages, together, two different thematic methods were used. Participation percentages were mapped using choropleth techniques, and the score data mapped using graduated symbols. In order to import the score and participation data into an ArcMap document, Excel spreadsheets were created and then the “join and relate” tool was used to sync the state-by-state data to the corresponding state. A base map of the United States was obtained from the U.S. Census website and utilized in the process of joining the score and participation data.
The participation data was classed into five different classes using the Natural Breaks/Jenks method. Five classes were deemed appropriate upon examining the data and determining that five classes most efficiently separated the data into logical groups without placing too many states into one group or another. The Natural Breaks/Jenks method of classification was chosen because the method uses an algorithm to class similar data values together and emphasizes the differences between classes. This method created a visualization of the data that allowed for easy identification of states with the highest, lowest, and similar participation rates.
The mean composite score data was symbolized using graduated symbols. While the score data could have also been symbolized using the choropleth technique, using graduated symbols and a vibrant color for those symbols created a visual hierarchy that placed emphasis on the scores for each state rather than participation percentages. The maximum and minimum size for the symbols was chosen so that the smallest value was easily visible and that the maximum value symbol would fit within each state and still leave enough room for labeling each state. Abbreviations were not used for the states to prevent users unfamiliar with state abbreviations needing to lookup abbreviations for states of interest. The score data was classed in a similar fashion to the choropleth data, five classes using the Natural Breaks/Jenks method of classification. The same procedure used for participation data was used for the score data, a visual inspection of the data followed by experimentation with class number and method, before determining that five classes using the Natural Breaks/Jenks method was appropriate for the data.
The projection chosen for the project was the Albers North American Equal Area projection. This decision was based on the desired map area containing all of the United States, and the inclusion of data suitable for choropleth mapping which is measured by enumeration unit (state), necessitating preservation of area. Because a projection that preserves area was chosen, moving Hawaii and Alaska from their exact geographic locations was necessary. Alaska is a large state and it was necessary to create an inset map to place Alaska along with Hawaii below the continental United States in order to ensure the continental portions were large enough to show the detail needed to display the data sets properly. Drop shadows were used to bring the states to the foreground and a bright yellow color used for the graduated symbols depicting the composite scores for each state. The choropleth data is displayed in shades of green to represent land mass and also the changing participation percentages between the states. The color change is gradual and a single hue of color is in use.
I thoroughly enjoyed the Cartographic Skills course and now that it is coming to an end, I feel that my GIS and cartographic skills have been greatly improved. Each assignment during the semester required me to utilize new skills and also those learned previously in Intro2GIS. I have to say that learning to use a new program, Adobe Illustrator, was my favorite aspect of the course. Prior to this semester I was restricted to creating and adding finishing touches to my maps in ArcMap with limited design choices, but now I feel confident that I can create visually appealing maps using Adobe.