Coloring maps

I am trying to make it easy to make high-quality maps for presenting model results. See: http://yetanothermathprogrammingconsultant.blogspot.com/2014/01/maps-from-gams.html. One rule of thumb: don't use a rainbow color scheme when trying to display numeric data. Here is an example where they actually seem to use random colors. Note that these colors do not help you to quickly grasp where high and low GDP growth occurs.

From: http://www.theguardian.com/business/interactive/2014/feb/14/eurozone-economic-growth-gdp-map.