The agricultural layer was based on global surfaces of agricultural area and production at 10 km spatial resolution (You and Wood, 2006). Agricultural census and survey statistics form the basis of these global surfaces. This statistical data was compiled at sub national administrative levels, usually the first or second subdivision of the national boundary of each country. These data are adjusted to the year 2000 using the official national figures that each country reports to FAO. Within administratives districts, the area and production for each 10 km pixel is estimated using a statistical model.
For the TNC layer, the area for the following crop surfaces were summed to calculate the total agricultural area for each 10 km pixel: Banana, Barley, Bean, Cassava, Coffee, Cotton, Groundnut, Maize, Millet, Other fibres, Other oil , crops, Other pulses, Plantain, Potato, Rice, Sorghum, Soybean, Sugar beet, Sugar cane, Sweet potato and Wheat.
Three categories are aggregations of several crops. "Other pulses" include cowpea, chickpea, pigeon pea and lentils. "Other oil crops" include coconut, sunflower, sesame, rapeseed and linseed. "Other fibres" include cottonseed, flax hemp, jute and others.