A bivariate choropleth map displays two variables on a single map by combining two different sets of graphic symbols or colors. It is a variation of simple choropleth maps that portrays two separate phenomena simultaneously while accurately and graphically illustrating the relationship between the two distributed variables. Bivariate Choropleth maps have the potential to reveal relationships between variables more effectively than side-by-side comparisons of the corresponding univariate maps.
The above Bivariate Choropleth map shows the relationship between crime rates and election results (votes for Kerry or Bush) in 2003.http://www.geog.ucsb.edu/~jeff/gis/choropleth_maps_files/election04_vs_crime03b.jpg
1 comment:
Molly - I want to make a map very similar to this. Do you have the SAS code? I would be so grateful...
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