How to measure a landslide

This is a map, courtesy of someone at the University of Michigan, of the election results by county, graded on a scale of "Strongly Obama" (bright blue) to "Strongly McCain" (bright red), with variations measured by shades between blue and red.

(FWIW, since when did the politically-left party become the "blue" party? They used to love being the so-called "Reds" ...)

It's an interesting map.