A geostatistical descriptor of the spatial distribution of soil classes, and its use in predicting the purity of possible soil map units

Abstract

A geostatistical descriptor of the spatial distribution of soil profile classes is discussed, the Sum of Indicator Variograms (SIV). This function may be estimated for a region from observations of the soil profile class occurring at a systematic array of sample sites, and fitted by an authorised variogram model. It is shown that the fitted variogram model can be used, given some simplifying assumptions, to predict the average purity of map units for a soil map of the region with a legend of simple units corresponding to the profile classes. An indication of the mean boundary interval of alternative maps is also given by the variogram model, although this should be treated with caution. The method proposed could therefore be useful when analysing observations from a reconnaissance soil survey, as an aid to selecting appropriate methods for more detailed survey.