Each color level represents a two-fold difference in maternal mortality rate.
Just a comment but I find maps easier to look at and interpret when the use two colors and degrees between them. Such as the maps you find on .Jmh649 (talk) 23:40, 15 May 2010 (UTC)
The color scheme you linked works well, but it allows only six levels. I've been trying to work out a color scheme that allows up to 18 colors to be recognizable, and to have a visually defined sequence. This seems especially desirable for maps like the one I've added here, which represent a vast logarithmic range. However, I am still in the process of working out what color scheme I like best, and if you describe which colors are most confusing I can test ways of working around them. (I've since begun using slightly different colors than those at right, particularly in the green and blue range) Mike Serfas (talk) 23:56, 15 May 2010 (UTC)