Cartographic Skills – Final Project

GIS 3015: Cartographic Skills

Final Project

Project Overview and Objectives

The final project involved the creation of a map to represent two independent sets of data (2013 scores and test participation) in relation to a test (ACT) taken by college-bound high school seniors.  The map is intended for publication in the Washington Post.  Skills necessary to complete the project included the ability to autonomously outline, design and complete the project, obtaining base map data from an outside source, applying a suitable projection, preparing tabular data in Excel, and classifying and symbolizing data.

Thematic Methods

Graduated colors and graduated symbols were used to symbolize the data.  Of particular interest, the base map data representing the United States did not have a defined projection.  The base map data was re-projected to Albers Equal Area Conic to preserve the area representation of the states to fairly represent scores and test participation rates in contrast to the size of the states across the United States.

Data Classification Methods

The Natural Breaks (Jenks) data classification method was used to represent the percentage of graduates tested with graduated colors.  The natural breaks method minimizes differences between data values in the same class and maximizes differences between classes thus clearly defining groups and breaks in the data for easy representation with graduated colors.  The data for the percentages of graduates tested fell nicely under five classes with ranges determined by the data’s natural breaks.  The 1 Standard Deviation data classification method was used to represent the average scores with graduated symbols.  The standard deviation was selected because it results in a fair comparison of the scores across states in relation to the mean score of all states as supported by the data.  The label was modified to display average score ranges instead of deviation to facilitate interpretation by the reader.

Design Techniques

A green color ramp was selected to represent the percentage of graduates tested with graduated colors because it was easy to identify the five classes (ranges) and it provided good figure contrast against the red school house used to represent average scores.  A red school house of a different size for each of the five classes (ranges) was used to represent the average scores for each state.  The school house matched the educational theme of the map and the red color was easy to see on the green background.  The size range was set from 10 to 30 so that each represented class (range) was five sizes apart thus making it easier for the reader to discern the various sizes against the legend.

  

The map below represents the 2013 United States ACT average scores and participation rates for high school graduates.