ABSTRACT
Various legacy soil data are available and can be used for digital soil mapping and particularly for the Global Soil Map creation. However, the structure of data, completeness, methodology of sampling and analyses, can differ significantly. The aim of this chapter is to highlight the principal problems in combination and harmonization of soil data from various resources and to illustrate these problems and their possible solutions on the example of soil data in the Czech Republic. The principal problems in combining and harmonizing the data are: various sampling designs (sample distribution, density, uneven coverage, completeness, localization), different sampling depths (fixed depths vs. horizons vs. topsoil only), differing sets of measured soil properties, different laboratory methods, data availability, age of data, missing uncertainty information.
