This study deals with the apparent resistivities measured by both Dipole arrays and Schlumberger array which is frequently used in resistivity sounding. Both have a connection with each other, which is shown by the equations of reciprocity between various electrode arrays, in the form given by Al'pin. These can be approximated as a linear summation by replacing their differential coefficients with formulae obtained by the use of the Lagrange interpolation polynomial. It is shown that this approximated transformation equation, which provides the Resistivity Sounding (RS) curve for the Dipole array from that obtained with the Schlumberger array, is adequate. Furthermore, the automatic interpretation method of Schlumberger RS curves which is an iterative one employing a non-linear least square technique can be applied to the automatic interpretation of Dipole RS curves, using the approximated equation stated above.
This paper contains a discussion on the above mentioned concepts, and the results of simple model experiments as well as ground measurements are included as case studies.