Demo/Upgrade software:

The latest updates to RES2DINV and RES3DINV require the Keylok dongle. Please note they no longer support the old Rainbow parallel port dongles which are more than 15 years old! Please contact on the procedure to exchange the Rainbow dongle for the new Keylok USB dongle. To download the last version that support the Rainbow dongle, go to the 'Legacy Versions' table below.

2D Resitivity & IP Inversion




A brief outline of the main features of this software (PDF format)


Res2dinvx32 ver. 3.71.118 software installation files, with support for multiple gradient array

Res2dinv ver. 3.59 Update File

For current users using Windows XP/Vista/7 - RES2DINV.EXE ver. 3.59.121 file only. To use this update, copy it so that it overwrites the old version in the appropriate folder in your hard-disk.


Res2dinvx32 ver. 3.71.118. New version of program with multi-core CPU support.
New inversion routines for time-lapse data. IP inversion using complex resistivity method.

Res2dinvx64 ver. 4.06.23 (Update file)

Res2dinvx64 (Setup file)

Res2dinvx64 ver. 4.06.23. 64-bit version of Res2dinv. Supports I.P. time-lapse data, and underwater survey with water area of limited extent such as a survey line across a levee or dam. Supports underwater surveys with suspended streamer betwen water surface and bottom.
The libiomp5md.dll must be copied to the same folder as the RES2DINVx64.EXE file.

Manual (English)

Manual for RES2DINV

Manual (Japanese)

Japanese version of manual for RES2DINV

Help File

Updated Windows Help file for RES2DINV


Program to generate support data files for RES2DINV. Not required for RSE2DINVx32/x64.

What's new

List of new features in RES2DINV

Vista and 7

Instructions for installing the dongle driver for Windows Vista and 7.


3D Resistivity & IP inversion




A brief outline of the main features of this software (PDF format)


RES3DINVx32 ver. 2.23.26 software installation files

Update File

For current users using Windows XP/Vista/7 - RES3DINV.EXE file only for ver. 2.16.91.
To use this update, the driver for your dongle MUST be installed, even for systems with Win XP/Vista/7.


Res3dinvx32 ver. 2.23.26. Version with support for multi-core CPUs. This version requires the Keylok dongle. Please note it does not support the old Rainbow parallel port dongles which are more than 15 years old! Please contact on the procedure to exchange the Rainbow dongle for the new Keylok USB dongle.

Manual (English)

Manual for RES3DINV

Help File

Updated Windows Help file for RES3DINV

What's new

List of new features in RES3DINV


Res3dinvx64 ver. 3.12.13 software installation file.

Res3DInvx64 Update File

For current users. Res3dinvx64.exe ver. 3.12.13 file only with complex resistivity inversion, sharp boundary option for 3-D floating electrodes surveys, model resolution calculation, underwater survey with arbitrary electrodes layout and time-lapse inversion (Professional version).
The libiomp5md.dll must be copied to the same folder as the RES3DINVx64.EXE file.


64-bit version of free 3-D forward modelling program. Res3dmodx64 ver. 3.05.12
Includes option for 4 nodes between electrodes and support for up to 128 GB RAM. Complex I.P. forward modeling.

Legacy Versions

There are the last versions of RES2DINV and RES3DINV that support the Rainbow dongle.




Res2dinv ver. 3.57 software installation file.


Res3dinv ver. 2.16 software installation file.

The RES2DINV and RES3DINV will operate in a 'demo' mode if the computer does not have the necessary dongle. The RES2DINV and RES3DINV demo programs are provided to enable potential customters to test the softwares before making a purchasing decision. In some cases, the free demo version has proved to be sufficient for the needs of the user. This is viewed as a demonstration of the usefulness of the softwares. However, technical support is only available for registered users of the full version of the softwares. If you want to purchase a copy of the full software version, please contact Geotomo Software or one of the authorised software distributors.

Hardware key (dongle) software drivers

This software driver from Rainbow Technologies or Keylok is necessary for current registered users who are running the above programs with Windows XP/Vista/7/8/10.

Rainbow Technologies Sentinel SuperPro dongle



System Drivers

System drivers for Rainbow Technologies hardware key

Sentinel Medic

Program by Rainbow Technologies to test the hardware key


Keylok dongle



System Drivers

System drivers for Keylok hardware key (includes support for Vista/7)

Keylok | Latest Keylok Driver | Keylok USB Vista Driver | System file for USB dongle | Dongle Checker

The types of dongles used by the RES2DINV and RES3DINV software.  Only the Keylok USB dongle is currently sent with the software package.

Use of a dongle on a computer without a parallel port
Many new notebook computers do not have a parallel port but come with at least one USB port. If you have one of the old parallel port dongles, the solution is to replace the parallel port dongle with a new USB dongle. Please contact on the procedure to exchange the dongle.

Free Software, Papers and Notes



Tutorial Notes - 26th. June 2016 Update

Lecture notes on 2D & 3D electrical imaging surveys.


Notes on electrical imaging in SPANISH

CD Files

Set of files for CD (20th. June 2017). Includes software, Tutorial Notes, abstracts and papers.

ZIP file with old versions

Old versions of Res2dinvx64, Res3dinvx32 and Res3dinvx64

Res2dinvx64/Res3dinvx64 programs files

Set of files installed with the Res2dinvx64 and Res3dinvx64 programs

ZIP file with extended abstract and slides

Rapid Inversion of Data from 2-D and from 3-D Resistivity Surveys with Shifted Electrodes, EAGE NSG 2015 conference paper

ZIP file with extended abstract and slides

Optimized Arrays for Resistivity Measurements Confined to the Perimeter of a Survey Area, EAGE NSG 2015 conference paper

ZIP file with extended abstract and slides

3-D resistivity inversion with electrodes displacements, ASEG 2016 conference paper


Extended abstract of ASEG 2013 paper "The inversion of data from complex 3-D resistivity and I.P. surveys" (PDF format)

Selected Journal Papers by M.H.Loke

(1). Loke, M.H. and Dahlin, T., 2002. A comparison of Gauss-Newton and quasi-Newton methods in resistivity imaging inversion. Journal of Applied Geophysics, 49, 149-162.

(2). Dahlin, T., Bernstone, C. and Loke, M.H., 2002, A 3D resistivity investigation of a contaminated site at Lernacken in Sweden. Geophysics, 60, 1682-1690.

(3). Marescot, L., Loke, M.H., Chapellier, D., Delaloye, R., Lambiel, C. and Reynard, E., 2003. Assessing reliability of 2D resistivity imaging in mountain permafrost studies using the depth of investigation index method. Near Surface Geophysics, 1, 57-68.

(4). Loke, M.H., Acworth, I. and Dahlin, T., 2003. A comparison of smooth and blocky inversion methods in 2D electrical imaging surveys. Exploration Geophysics, 34, 182-187.

(5). Chambers, J.E, Loke, M.H., Ogilvy, R.D. and Meldrum, P.I., 2003. Non-invasive monitoring of DNAPL migration through a saturated porous medium using electrical impedance tomography. Journal of Contaminant Hydrology, 68, 1-22.

(6). White, R.M.S., Collins, S. and Loke, M.H., 2003. Resistivity and IP arrays, optimised for data collection and inversion. Exploration Geophysics, 34, 229-232.

(7). Loke, M.H. and Lane, J.W., 2004. Inversion of data from electrical resistivity imaging surveys in water-covered areas. Exploration Geophysics, 35, 266-271.

(8). Nguyen, F, Pirard, E., Garambois, S, Jongmans, D. and Loke, M.H., 2005. Image processing of 2D resistivity data for imaging faults. Journal of Applied Geophysics, 57, 260-277.

(9). Loke, M.H., Chambers, J.E. and Ogilvy, R. D., 2006. Inversion of 2-D spectral induced polarization imaging data. Geophysical Prospecting, 54, 287-301.

(10). Tonkov, N. and Loke, M.H., 2006. A resistivity survey of a burial mound in the Valley of the Thracian Kings'. Archaeological Prospection, 13, 129-136.

(11). Linderholm, P., Marescot, L., Loke, M.H. and Renaud, P., 2008. Cell Culture Imaging Using Microimpedance Tomography. IEEE transactions on Biomedical Engineering, 55, 138-146.

(12). Sjödahl, P., Dahlin, T., Johansson, S. and Loke, M.H., 2008. Resistivity monitoring for leakage and internal erosion detection at Hällby embankment dam. Journal of Applied Geophysics, 65, 155-164.

(13). Hilbich, C., Marescot, L., Hauck, C., Loke, M.H. and Mäusbacher, R., 2009. Applicability of ERT Monitoring to Coarse Blocky and Ice-rich Permafrost Landforms. Permafrost and Periglacial Process, 20, 269-284.

(14). Rucker, D.F., Loke, M.H., Levitt, M.T. and Noonan, G.E., 2010. Electrical Resistivity Characterization of an Industrial Site using Long Electrodes. Geophysics, 75, WA95-WA104.

(15). Loke, M.H., Wilkinson, P.B. and Chambers, J.C., 2010. Fast computation of optimized electrode arrays for 2D resistivity surveys. Computers & Geosciences, 36, 1414-1426.

(16). Loke, M.H., Wilkinson, P.B. and Chambers, J.C., 2010. Parallel computation of optimized arrays for 2-D electrical imaging surveys. Geophysical Journal International, 183, 1202-1315.

(17). Chambers, J.E., Wilkinson, P.B., Wealthall, G.P., Loke, M.H., Dearden, R., Wilson, R., Ogilvy, R.D., 2010. Hydrogeophysical Imaging of Deposit Heterogeneity and Groundwater Chemistry Changes during DNAPL Source Zone Bioremediation. Journal of Contaminant Hydrology, 118, 43-61.

(18). Loke, M.H., 2011. Electrical resistivity surveys and data interpretation. in Gupta, H (ed.), Solid Earth Geophysics Encyclopaedia (2nd Edition) "Electrical & Electromagnetic",Springer-Verlag, 276-283.

(19). Loke, M.H., Chambers, J.E. and Kuras, O., 2011. Instrumentation, electrical resistivity. in Gupta, H (ed.), Solid Earth Geophysics Encyclopaedia (2nd Edition) "Electrical & Electromagnetic", Springer-Verlag, 599-604.

(20). Rucker, D.F., Fink, J.B. and Loke, M.H., 2011. Environmental Monitoring of Leaks using Time Lapsed Long Electrode Electrical Resistivity. Journal of Applied Geophysics, 74, 242-254.

(21). Wilkinson, P.B., Loke, M.H., Meldrum, P.I., Chambers, J.E., Kuras, O., Gunn, D.A. and Ogilvy, R.D., 2012. Practical aspects of applied optimized survey design for electrical resistivity tomography. Geophysical Journal International, 189, 428-440.

(22). Rucker, D.F., Crook, N., Glaser, D. and Loke, M.H., 2012. Pilot-scale field validation of the long electrode electrical resistivity tomography method. Geophysical Prospecting, 60, 1150-1166

(23). Chambers, J.E., Wilkinson, P.B., Penn, S., Meldrum, P.I., Kuras, O., Loke, M.H. and Gunn, D.A., 2013. River terrace sand and gravel deposit reserve estimation using three-dimensional electrical resistivity tomography for bedrock surface detection. Journal of Applied Geophysics, 93, 25-32

(24). Loke, M.H., Chambers, J.E., Rucker, D.F., Kuras, O. and Wilkinson, P.B., 2013. Recent developments in the direct-current geoelectrical imaging method. Journal of Applied Geophysics, 95, 135-156

(25). Loke, M.H., Wilkinson, P.B., Chambers, J.E. and Strutt, M., 2014. Optimized arrays for 2-D cross-borehole electrical tomography surveys. Geophysical Prospecting, 62, 172-189

(26). Loke, M.H., Dahlin, T. and Rucker, D.F., 2014. Smoothness-constrained time-lapse inversion of data from 3-D resistivity surveys. Near Surface Geophysics, 12, 5-24

(27). Loke, M.H., Wilkinson, P.B., Uhlemann, S.S., Chambers, J.E. and Oxby, L. S., 2014. Computation of optimized arrays for 3-D electrical imaging surveys. Geophysical Journal International, 199, 1751-1764.

(28). Loke, M.H., P. B. Wilkinson, P.B. , Chambers, J.E., Uhlemann, S.S. and Sorensen, J.P.R, 2015. Optimized arrays for 2-D resistivity survey lines with a large number of electrodes. Journal of Applied Geophysics, 112, 136-146.

(29). Wilkinson, P.B., Uhlemann, S., Chambers, J.C., Meldrum, P.I. and Loke, M.H., 2015. Development and testing of displacement inversion to track electrode movements on 3-D electrical resistivity tomography monitoring grids. Geophys. J. Int., 200, 1566-1581.

(30). Wilkinson, P.B., Uhlemann, S., Meldrum, P.I. Chambers, J.C., Carriere, S., Oxby, L.S. and Loke, M.H., 2015. Adaptive time-lapse optimized survey design for electrical resistivity tomography monitoring. Geophys. J. Int., 203, 755-766.

(31). Loke, M.H., Kiflu, H., Wilkinson, P.B., Harro, D. and Kruse, S., 2015. Optimized arrays for 2-D resistivity surveys with combined surface and buried arrays. Near Surface Geophysics, 13, 505-517.

(32). Dahlin, T. and Loke, M.H., 2015. Negative Apparent Chargeability in Time-domain Induced Polarisation Data. Journal of Applied Geophysics, 123, 322-332.

(32). Wilkinson, P., Chambers, J., Uhlemann, S., Meldrum, P., Smith, A., Dixon, N. Loke, M.H., 2016. Reconstruction of landslide movements by inversion of 4-D electrical resistivity tomography monitoring data. Geophysical Reserach Letters, online, 10.1002/2015GL067494.

PowerPoint Slides

PowerPoint slides from various NSG and ASEG conferences. A simple and visual introduction to various topics on 2-D, 3-D and 4-D inversions.


Copper Hill mineral deposit 3D IP survey and inversion modelling by Arctan Services Pty., Australia


Web site with publications on electrical imaging in Spanish


Report of geophysical survey in the Afar region (Ethiopia) by NGO Action Against Hunger. The search for groundwater in a harsh but beautiful land by electrical imaging.


Free 2D Resistivity and IP forward modelling software (Windows version 3.03.03)
Calculate apparent resistivity for non-standard arrays surveys.


Free 3D Resistivity and IP forward modelling software, Windows ver. 2.14.21


Simple and free 1D resistivity and IP program, ver. 1.00.09. This is a free non-commercial program released for academic use. It is not intended for commercial use (see the X2IPI program under 'Electrical Data Processing' link below for commercial use).


Free 1-D frequency domain EM modeling program for the EM-34 type of instrument.

Links to other useful software



PDF Reader

Free Adobe Acrobat Reader program for PDF files

Text Editor

GWD Text Editor for Windows (shareware)

Graphics Editor

Neopaint graphics editing software (shareware)

Electrical Data Processing

Software to edit resistivity and IP data, includes a commercial 1D inversion software


Site for various demo and shareware programs

2D plotting

Demo for Surfer 2D plotting software

3D graphics and models

A sophisticated 3D earth science graphics package. Supported by RES3DINV.

2D and 3D graphics package

Includes functions to directly import model information from RES2DINV/RES3DINV

3D plotting

Demo for Slicer/Dicer 3D plotting software


ParaView free opensource 3D visualization software | |