RES2DINV software is designed to interpolate and interpret field data of electrical geophysical prospecting (2D sounding) of electrical resistivity (conductivity) and induced polarization. The inversion of the resistivity and IP data is conducted by least-square method involving finite-element and finite-difference methods. The software can handle data from any electrode array, including Wenner (a, b, g), dipole-dipole, inline pole-dipole, pole-pole, Wenner-Schlumberger, equatorial pole-dipole and non-conventional arrays. Interpolate data from land, under water, and cross-borehole surveys. Easy data conversion from the most popular geophysical instruments including ABEM Lund, Syskal, AGI, PASI, IRIS, SCITREX, etc.