f The resistivity grid to optimize tomographic 3D imaging

In this paper a modified version of the old resistivity "AB rectangle" is presented. Here the potential electrodes are located along a regular grid of suitable dimensions, having a triangular or square unitary cell. The current electrodes, instead, are generally located outside of the grid (see figure below), and various directions of the transmitting dipoles may be selected so to optimize the lighting of the subsoil under investigation (as expected the results improve by increasing the number of the directions).