This work presents a methodology for horizontal soil stratification and a device for 3D soil mapping using the discretization of the Wenner’s method. The methodology starts from the application of the lateral profiling method in conjunction with the Wenner’s method to find the experimental resistivity curve. The Sunde’s algorithm is used to construct the theoretical resistivity curve. By utilizing these experimental and theoretical resistivity curves, it is possible to apply the optimization process to find the parameters: electrical conductivity and thickness of each soil layer. The area under study is discretized and the results related to all subareas are unified using interpolation process. The whole process which results in 3D soil mapping may be automatically produced using the proposed device.