Lisa Keys-Mathews
lmathews@unanov.una.edu
Department of Geography
University of North Alabama

OBJECTIVES

• To gain an understanding of data classification methods using data and boundaries provided through the ArcView geographic data representation program;
• To compare and contrast classification methods and to study the spatial patterns represented by different classification methods; and
• To create three choropleth maps of the United States by county or the World by country.

Using ArcView, peruse the data available with ArcView and choose a data set of interest to you from various ArcView directories on your computers. The data set must be accurate to the county level for the United States or to the country level for the world. This is a choropleth map and you must choose the correct type of data to map (i. e., you must choose data that is a percentage, rate or ratio; not absolute values).

Create four maps; one for each of the following classification methods: Equal Interval, Natural Breaks (Jenk's Miniumum Variance), and the Quantiles. (Note that these are all options for ArcView.) Use the same number of categories for each map, for comparison purposes. The number of categories you choose should be based on trial and error (meaning that you should experiment with different numbers of categories to determine which best separates for your data. Make sure you choose colors or textures that display your data properly.

Finally, create a report that explains the methods, compares the results of the three methods, explain how each method displays your data, which method is best for your data set, and what are the advantages and disadvantages of each method for your data.

In addition, interpret the information on each map. What can you infer from the data? How does the method that best represents your data compare to the others in the interpretation of the data? What spatial patterns do you see on each map? How do the spatial patterns compare to each other? How do the spatial patterns relate to the classification method? What interpretation mistakes can be made if the wrong classification system is chosen? Make sure that your maps are labeled according to the classification method used and are referenced in your paper. Include a bibliography if you get any information from a source other than your own heads. Additional documentation is available for ArcView, if necessary.