-- Data Source:
http://koeppen-geiger.vu-wien.ac.at/present.htm

Download "code with raster file:   Map_KG-Global.R"


-- Bulding:
g++ asc2a.cpp texture.cxx -o asc2a -lGL -lz -losg


-- Workflow:
1. Convert the ESRI grid to ASCII using R:
   https://groups.google.com/forum/#!topic/maxent/OrTBUvqOXaE

2. Run asc2a to convert the ASCII file to a single channel rgb file:
  ./asc2a <infile>.asc <outfile>.rgb

3. Use your favorite image processing package to convert from rgb to png
   to compress it 40x compared to the ESRI grid image and 110x compared to
   the ASCII file.