These visualizations were performed for FAO AQUASTAT.
These treemap charts allow for hierarchical organization of information of different types. In the image above, for example, the irrigation areas for each country are represented as the big boxes, within which the technology utilization is displayed in different colors. This allows users to see a large amount of information quickly.
View more irrigation area treemaps, and a detailed analysis on the AQUASTAT website:
http://www.fao.org/nr/water/aquastat/irrigationdrainage/treemap/index.stm