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.