Assignment: Data Classification and Choropleth mapping


  1. Download this table of data of the US by state. This table has data of the median in 2005 and 2014, and the difference. Classify and map one of these columns into five categories using one of the four data classification methods explained here: equal interval (equal steps), quantile, natural breaks, and standard deviation approaches.
  2. Determine the number of observations in each category using the Excel FREQUENCY function. This video explains how this works.
  3. Create a legend for each classification method, as depicted below, that includes the number of observations in each category. Use this Illustrator template file. Save as "legend.png" and link from your webpage.
  4. For your finished map, choose one of the data variables in the Excel file, and one of the classification methods below. Shade your map with ColorBrewer. When designing the layout, incorporate some of the design ideas from this set of examples.
  5. Link your Excel file with the four tabs for each classification from your website. Link the completed illustration below, your Excel file, and the finished map. The html code would look something like this:
 <li>Week X: <a href="4xLegend.pdf"> <img src="4xLegend.png" height=64> Legends </a> || <a href="US_median_age.xlsx"> Excel file </a>||<a href="MedianAge.pdf"> <img src="MedianAge.png" height=64> Map of Median Age </a> <br /> </li> 


6. Convert the legend you choose for your map to a horizontal histogram using Illustrator's graphing function || Youtube instructions


Ungroup and delete the extraneous graph elements. Shade with ColorBrewer. Add numbers to each bar to indicate the number of values in that category.