High Accuracy Surface Modeling Method Combined With Auxiliary Variables For Soil Mapping

High accuracy surface modelling (HASM) is a spatial interpolation technique based on the fundamental theorem of surfaces, which can be applied to soil property interpolation. This study proposed modified HASM methods combined with ancillary variables for improved interpolation of soil properties. To evaluate the performance of HASM, we compared its performance with other classical methods such that ordinary kriging (OK), ordinary kriging combined geographic information (OK-Geo), stratified kriging (SK), and so on. To do so, predicted and measured values were compared using the mean error (ME), mean absolute error (MAE), root mean square error (RMSE) and prediction efficiency (PE). The results have shown that HASM generally performs better than the other methods with a lower estimation bias. Much more details were presented in the HASM maps for soil properties due to the combination of different types of geographic information which gave abrupt boundary for the spatial variation of soil properties.