The FAO-UNESCO Soil Map of the World 912:631.4(100) F73 was published in 19 separate sheets in 1974. It took 15 years to produce it, and it was published at a 1:5 million scale. The map is based on information contained in some 11000 separate larger-scale maps.
Four basic variables are included on the soil map. The soils are divided into 26 major groups and are further subdivided to give a total of 106 individual soil units. The map also specifies three categories of texture and of slope. Information is also included on 12 different soil phases, such as stoniness and salinity.