Rendering rules provide a powerful way to control how and when a layer is displayed relative to other layers or to the properties of the layer itself. Using a rule-based renderer, this recipe demonstrates how to color code a layer based on an attribute.
You will need to download a zipped shapefile from https://geospatialpython.googlecode.com/svn/ms_rails_mstm.zip.
Unzip it and place it in the directory named ms
in your qgis_data
directory.
In this same directory, download and unzip the following shapefile:
https://geospatialpython.googlecode.com/files/Mississippi.zip
Finally, add this shapefile to the directory as well: