Is it possible to randomly color polygons?

[Stephen Woodbridge]

Jeff Hoffmann wrote:
> I have a layer with a lot of polygons that I want to display, but I 
> don't really care about what color those polygons are (they're not 
> classified, I'm not going to have a legend, I just want them to be 
> different colors so no 2 adjacent polygons are the same color, e.g. 
> counties in a state or states in the US).  It seems like it'd be a 
> pretty common thing to want, but is there a reasonably easy way to do 
> it?  I'm guessing the best way would be to assign a class to each of the 
> polygons, but is there some sort of algorithm to figure out how many 
> colors I need and how to assign them?
> 
> Any ideas?
> 
No, color randomly does not work, You need to apply the Four Color 
theorem, see:

http://www.math.gatech.edu/~thomas/FC/fourcolor.html

Your best bet is to apply this to the polygons first and set an 
attribute column dor a color number and then as you suggest use 
mapserver class to select and render the color.

-Steve