2Department of Environmental and Sedimentary Geology, Institute of Geosciences, University of São Paulo, São Paulo, Brazil
A simple but novel and applicable approach is proposed to solve the problem of smoothing effect of ordinary kriging estimate which is widely used in mining and earth sciences. It is based on transformation equation in which Z scores are derived from ordinary kriging estimates and then rescaled by the standard deviation of sample data and the sample mean is added to the result. It bears the great potential to reproduce the histogram and semivariogram of the primary data. Actually, raw data are transformed into normal scores in order to avoid asymmetry of ordinary kriging estimates. Thus ordinary kriging estimates are rescaled using the transformation equation and after that back-transformed into the original scale of measurement. For testing the proposed procedure stratified random samples have been drawn from an exhaustive data set. Corrected ordinary kriging estimates follow the semivariogram model and back-transformed values reproduce the sample histogram, while keeping local accuracy.