At present no standards, definitions or criteria exist for the assembly, mapping and interpretation of soil legacy data sets, case definitions, soil health and degradation, diagnostic tests, and sampling designs for assessing and monitoring soil condition. It is thus difficult to derive spatially and temporally consistent evaluations of the occurrence of soil degradation, or to provide evidence-based management recommendations for maintaining and improving soil health. One of the primary activities in the project is therefore to set standards for soil data and evaluation criteria. In the production of base maps, substantial effort is being be devoted to assembling and harmonizing satellite images, satellite image time series and digital terrain models. We are producing large-area mosaics of radiometrically calibrated, orthorectified Landsat MSS, TM and ETM+ images. We are also developing SRTM terrain model derivatives (e.g. terrain units, slopes, curvatures, contributing areas, compound topographic and erosion/deposition indices and watershed delineations). These datasets will be available through interactive map interfaces, and for download. There are some notable problems associated with using soil legacy data for soil mapping and surveillance. For the most part, soil legacy data were not purposely sampled to cover large areas using statistical sampling criteria and randomization procedures, and are thus not representative of the overall condition of soils in SSA.

To address these problems, the AfricaSoils.net project is conducting field surveys and establishing soil health baselines in 60 sentinel sites covering a wide range of environmental conditions in SSA. The establishment of sentinel sites and field survey locations is done using a spatially stratified random sampling approach, which will provide us with the first unbiased sample of the sub-continent.

This includes ~17.5 million sq.km of continental sub-Saharan Africa (SSA) and 591,740 sq.km of Madagascar, giving a total of ~18.1 million sq.km covering 42 countries. The area excludes hot and cold desert regions based on the recently revised Köppen-Geiger climate classification developed at the University of Vienna, as well as non-desert areas of Northern Africa, small island nations, protectorates and national territories.