Mapping soil typologies : spatial decision support applied to the European Soil Database

For many applications of modelling environmental conditions or processes soil characteristics are needed in form of spatial data ready to be integrated in a GIS. A source of uniform data on characteristics of European soils is available from the European Soil Database (ESDB) of the European Soil Bureau. The soil information was collected by participating national institutions and underwent an extensive process of harmonizing the thematic content of recording the soil characteristics and ensuring spatial continuity along boundaries. In the database a many-to-1 link is used to relate soil characteristics to the geographic .layer. Thus, considerably effort is required to represent specific soil characteristics in a single spatial layer. In this evaluation of the ESDB an attempt was made to position the soil typological units within the spatial units. The approach followed in this study for the spatial disaggregation of typological units was to link the data from the soil typology table with thematically corresponding ancillary spatial data. For the spatial allocation a multi-criteria analysis within the framework of a spatial decision support system (sDSS) was used. This approach allows generating single raster layers for any of the soil characteristics, independently of the data type. This greatly simplifies the mapping of soil characteristics and allows the use of the complete pool of information available in the ESDB. However, in the absence of an estimation of uncertainties in the source data issues of model uncertainties remain to be addressed.