Maps For the (Color)Blind
7-10% of males have trouble telling the difference between this and this. Why should a mapmaker care? Well, if you want your map to be intelligible to as many people as possible, you should probably not use a red-green color scheme. Unfortunately, many, many mapmakers have forgotten this fact.
The last of these maps being just about the most misguided map I have ever seen (but more on that later).
All of these were found in just a few minutes on Google, meaning that unfortunately, red-green maps are everywhere. Still, this is no excuse for adding to the pile. Even though it might be common to forget about them, the colorblind need maps too, and it is pretty damn easy to select any other color scheme than red-green. So please do.