This is such a good explanation of soil resistivity and soil layers. My interest is in the electrical field and earth grid design, this explanation is far easier to understand than the many electrical models I've seen, well done.
This is excellent. I've used interpex over the the years. The problem has been the changes made in MN which had distorted the production of excellent curves during iterations . GeoVes has solved that problem. I'll need a link to try GeoVes.
It looks very useful - thank you for putting it out there for free. If one has the equipment, it is good to add IP measurements to the sounding as it can resolve some of the equivalence problems but also distinguish between a saline gravel layer and a clay or shale formation. The sortware would have to be modified for chargeability but that is not too difficult using Siegel's formula.
You are welcome George! GeoVES is just a simple tool I developed some 20 years ago in Ghana. You are right - IP is useful, but I don't have much experience with it. I have tried it in Ireland for mineral exploration, but I remember we needed much higher currents than a normal resistivity survey (we almost killed a cow who was eating our cable...) and also special non-polarising potential electrodes. Most of the equipment I have come across in the places where I normally work would not be suitable for this. All the best, Andreas
@@GeosearchInternational There are low-power systems (AGI Sting) which can use IP on multi-cable ERT systems. The larger systems for mineral exploration use higher currents and therefore higher voltages and with gradient arrays they can be dangerous as electrodes might be out of sight. Cattle eating cables is indeed a problem! I'll drop you an email. Regards, George
Nice to know that you worked in beautiful agricultural fields of Punjab Pakistan. I am also originally from Punjab and first time I did this type of survey during my Bachelor studies at the University of Agriculture Faisalabad. Thanks for the video
Fieldwork in such a beautiful irrigated area is one of the highlights of the job! I was working on the Lower Bari Road Canal (LBDC) & based in Lahore. The geophysicists in the video did a really great job & had much better data than what many produce with "advanced" resistivity equipment. All the best, Andreas
@@GeosearchInternational where are you based originally? I am really impressed the amount of field work you did. I am modeller and always dream of such a data collection experience in career.
I grew up in Africa & Asia, was educated in UK and then I have been working in over 30 countries in Europe, the Middle East, Africa & Asia. The world is my home. All the best, Andreas
Great work done..! Thanks for sharing your great effort by making such software that is much easy to understand the basics of the VES. Have you develop something similar for the wenner array configration. If yes kindly share that as well. Thanks in advance.
You are most welcome Muhammad! Sorry, I do not use the Wenner array as Schlumberger has many advantages for groundwater exploration. All the best, Andreas
Hi Andreas, I am trying to create my own inversion software for a university project and I am struggling to calculate an accurate modelled apparent resistivity value when using the inversion model. So far I have managed to find a solution for the forward modelling resistivity transform function of a Schlumberger array to be: Ti(λ) =ρi(1 − e^−2λhj) + Ti+1(1 + e^−2λhj)//ρi(1 + e^−2λhj) + Ti+1(1 − e−^2λhj). Where ρi and hj are the estimated true resistivity and thicknesses for each layer respectively, Ti is the modelled apparent resistivity, and λ is the electrode parameter. I have tried plugging in some of the data used in this video and so far there has been no success! Any help would be greatly appreciated! Thanks :)
Hi Jack, In GeoVES I used Gosh linear filters. It works quite well for Africa where we have weathered regolith ontop of infinite resistive basement. If the bottom layers have a lower resistivity, Gosh is not optimal. I think O'Neill's filters are better. Please see below a link to his paper: drive.google.com/file/d/1_9D1drGDKk2BkS1RiPFqD7q4hCFnbBme/view?usp=share_link Also have a look at the Excel tool made by @MolanoCarlos th-cam.com/video/9QZh688d1lQ/w-d-xo.html Good luck & all the best, Andreas
Hello, sir, thank you for making a data processing tutorial using the Geoves method, now I'm trying to process data using Geoves software, but I have difficulty in the modeling section entering the resistivity value and thickness value because the red line does not merge at the dots
I have difficulty in the modeling section entering the resistivity value and thickness value because the red line does not merge at the dots white circle even though I have entered a value that matches the data. I hope that you will read and reply to my comments Thank you sir
Have you tried fitting a model to the example from the video? If not, try that first. Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg All the best, Andreas
Hello sir Hope this comment finds you well Sir, my name is Hidir and I am a geophysics student and I benefit a lot from the educational videos that you publish, so I would like to thank you very much for them. I have a question that baffles me, and I hope you will answer me if you please. Question: After we put the data in the excel file and interpreted the VES, how do we determine the locations of groundwater if we do not have information about wells nearby in the area?? Then how can we determine the amount of water that can be extracted from the water-bearing layer of this interpreted section? waiting for your answer thank you
Hi Hidir, Have you seen my video on Groundwater Exploration Strategy, where I try to explain how I normally approach this complex topic? th-cam.com/video/3c0iPjM65JU/w-d-xo.html Basically, the geophysical survey should come after you have completed a desk study and baseline survey of the project area. That way you can better interpret the VES data. You need to develop a conceptual hydrogeological model first. The VES just helps you to select sites for exploration drilling. e.g. where is the deepest aquifer thickness, or where is the fracture zone. Once you have a successful well, you need to carry out pumping tests to measure its hydraulic effectiveness (step tests) and how much water you can extract (constant rate & recovery tests). I have made a couple of pumping test videos, but there are still more to come. All the best, Andreas
Hi Gustavo, You are welcome & glad you liked the video. In the Schlumberger array, the electrode separation AB must be at least 5 times separation MN. i.e., AB >= 5 * MN For our first MN separation of 1m, AB should be at least 5m i.e., MN/2 = 0.5m needs at least AB/2 = 2.5m OK, so that is the theory. In the field we need to keep things as simple as possible, so that is why we start with MN = 1, and then record AB/2 of 2, 3, 4, 5, 6, 8, 10, 15 m etc. Actually the data should only be valid above AB/2 of 3m, but it does not harm to get a reading before at AB/2 of 2m, so that the field team starts to wake up. I usually discard the first data point anyway as it is often affected by noise/operator error. In the VES example of the video, the field data was collected in Pakistan by a geophysicist starting with an AB/2 of 1.5, which is maybe a bit too small, and then he misses out some extra measurements I would normally do in order to save some time. He jumps to 3, 5, 7, 10m but the data quality is good, which is what is important. What I wanted to show with this example is that a guy using a pencil and paper and a really ancient resistivity meter can produce better data than someone with the latest high tech equipment who does not know what he is doing. Geophysics is all about good field techniques, not just pushing buttons. Of course it is important to also keep the theory in your mind & I'm glad you are asking yourself the right questions! All the best, Andreas
I am using ERT by Schlumberger array. My desired depth of investigation is up to 30m. So please can you tell me how much array length I have to consider so that I can get resistivity up to 30m depth ? It will be a great help. Do i need to take data at different AB,and MN values or can i directly select the one array length with higher spacing AB ?
Hi Suraj, Please see below the field sheets I would normally use for VES. Schlumberger VES Fieldsheet PDF: bit.ly/3ziyeql2 Schlumberger VES Fieldsheet XLSX: bit.ly/3IXCDT22 Sorry I cannot advise you on ERT. You will need to check the manual. Normally AB needs to be at least three times the depth of investigation but you will need to check with the equipment you are using. I dont understand you question fully, as ERT is normally done using 5 or 10m electrode intervals with multi-core cable. If you are referring to a simple electrical resistivity traverse, the recommended method would be to collect 2 sample points per location. So if you want to explore the 20-30m depth interval you could maybe use AB 100m & AB 60m plus whatever the correct MN is for that. All the best, Andreas
Hi,, can you prepare a comprehensive video of how a lay man can understand the groundwater potential point in a given area for borewellz and recharge wells ? Tanx fr your valuable videos
Hi @its Me, Glad you like the videos! Have you seen my video on Groundwater Exploration Strategy, where I try to explain how I normally approach this complex topic? th-cam.com/video/3c0iPjM65JU/w-d-xo.html All the best, Andreas
This is a very well explained and overall great video! As I am now starting to write my master dissertation about humanitarian geophysics, may I know how can I cite this excel program to my dissertation? Since, I might be using this later in my field test. Thank you. And also does it work for Wenner array configuration too?
Thanks for your kind words Bagoes! I guess you could just link to the video & the file. Something like: Hydrogeology 101: GeoVES - Free 1D VES inversion for groundwater exploration. Link to the video on TH-cam: th-cam.com/video/EN0-Fhan3fs/w-d-xo.html Link to GeoVES Master XLS file: bit.ly/2OpcMvm It is designed for Schlumberger configuration only. I don't recommend Wenner for groundwater exploration, if you want to do VES. All the best, Andreas
We thank you releasing an important video showing how to analyze electrical resistivity data using excel. I need know difference the excel program an ipi2win software in analysing such data because geophysical survey for groundwater investigation using electrical resistivity method is my undergraduate project. I need to the differences before making decision of which one to use. Thank you. Best regards.
Hi Salihu, I developed GeoVES 20 years ago because I wanted a program which allowed me better quality control of the data and manual curve fitting. This makes it also a much better teaching tool than other options like the one you mentioned. For your decision the most important consideration is not which program is better, but what your professor thinks who will mark your work. Better you talk with your professor. Alternatively why not try both and find out what the difference is? Good luck and all the best, Andreas
Another important advice is that you should spend even more time thinking about what field procedures you will use to make sure that you collect good data. If the data is not good, no program can fix it later. All the best, Andreas
Andreas, gratitude for the illustrative teaching. I really enjoyed your explanations using animations in the first and this second video. What if I only have my AB/2 values, MN values and apparent resistivity values directly from my resistivity meter (tetrameter). How do I use the software to plot or is there a different software?
You're very welcome Ayeni! If you want to use GeoVES, you will need to calculate deltaV/I from the other values, and fill in the data in the green cells of the Data sheet. Alternatively you can maybe try to paste your AB/2 and Apparent resistivity data into the Model sheet, but I have never tried this so not sure if it will work. Let me know if you succeed. All the best, Andreas
Hello Ayeni, we have the same equipment (Abem Terrameter 1000), i also have AB/2, MN/2 and apparent resistivities....did you find a way to use this excel program?
Sorry I don't use IPI2WIN, I use GeoVES which does everything I need and is much more transparent in how the data is processed. For 2D sections I use Excel to line up the different geoelectrical models or RES2DINV if there is a lot of data - for example from a resistivity profile. All the best, Andreas
@@GeosearchInternationalsir, you being a hydrogeologist what will be your suggestion about which topic is the best to take as a project in hydrogeology?
@@abubakkarsaddique8909 You mean for a university project? You need to get high marks so best to chose a subject which whoever is marking you likes. Of course you should also enjoy that subject! The most important thing is to have good data, so I would chose the project based on data availability. I would not advise doing any modelling, at least not as the core of the project as many models take a long time to calibrate and you need lots of prior experience to make them work. Good luck and all the best, Andreas
@@GeosearchInternationalCurrently, I have the intention to choose a project as a VES base as I have very much data already available and I want to collect new data and correlate that and plus touch the hydrology little..so I need your view about it?
Hi Yusuf, the links to the files are always in the description below the video. Link to GeoVES Master XLS file: bit.ly/2OpcMvm Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg Link to the video on TH-cam: th-cam.com/video/EN0-Fhan3fs/w-d-xo.html Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html All the best, Andreas
Hello sir, it is really an easy and handy spreadsheet. However, I want to know how to increase the MN columns in the spreadsheet. As I Have more than 5 MN values ie., 2, 8, 10, 20, 30, 40, 50 in my VES survey.
Hi Neeraj, Adding new MN columns means a redesign of the spreadsheet, so it is not possible. In any case you should not have so many MN changes, as for each change you need to take overlapping readings to correct for any changes in near surface resistivity. I will make a video about this at some stage. Please see below the field sheets I would normally use: Schlumberger VES Fieldsheet PDF: bit.ly/3ziyeql2 Schlumberger VES Fieldsheet XLSX: bit.ly/3IXCDT22 All the best, Andreas
Thank you sir. Just wanted to clear my doubt sir. When am keeping the same V/I values as you have provided in given Punjab sample one, am getting different resistivity values and in graph the points obtained are not in a curve sir. Kindly correct me if am doing it in a wrong way
Dear Faisal, In the video description I have provided the link to GeoVES example from Punjab: bit.ly/3rQPRXg Download the file by clicking on the down arrow in the top right of the screen. All the best, Andreas
I can't change for MN and the valua of P resistivty because your resisty data and my resistivty data isnot same so can i get the blank sheet we get it our own data ?
Hi @abdikaniibrahim6091, GeoVES is only for Schlumberger soundings & you need to enter the required data in the green cells, which are: AB/2, MN and deltaV/I. What data does your equipment collect? All the best, Andreas
Hi Andes, I guess you mean the geometric factor (K)? In GeoVES it is fixed for the Schlumberger array, so your data cannot be in other arrays. Please check that you are using the correct MN/2 and AB/2 distances. Good luck and all the best, Andreas
@@GeosearchInternational Dear Andreas, i mean if in the Schlumberger array the MN distance (distance between inner electrodes) is defined like 1, 10, 100 or it can be fixed as more accuracy is required, or if it had to accomplish other condition beside good practices like 'the distance between current electrodes must be at least 5 times the distance between potencial electrodes'. i ask this question because the terrain in which the measures was taken had a lot of rocks buried, and in the graph show a big jump between fixeds MN = 2 and MN = 6 . Thanks in advance
Hi Andes, Yes, in theory AB should be >=5 x MN. I usually use MN of 1, 10, 60 & 200m. Basically you only increase the MN distance when you see that the signal is getting weak and you cannot do anything about it like injecting more current, hammering the current electrodes deeper or adding salty water. Then you move up to the next MN distance, but make sure that you have at least 3 overlapping readings with the previous MN distance so you can correct any offsets later on. The data quality depends on how clean your readings are. I always take three separate readings at any location and make sure that they are very similar. If not - hammer electrodes/add water etc... There is no point in averaging the readings as a bad reading will not improve itself. I am planing to make a video about this when I have time. Please have a look at the field sheets below to get a better idea. One last point: always plot your data in the field! Schlumberger VES Fieldsheet PDF: bit.ly/3ziyeql Schlumberger VES Fieldsheet XLSX: bit.ly/3IXCDT2 All the best, Andreas
Hi Nean, ρa = K * ∆V/I, where ρa = the Apparent Resistivity (ohm-m) K = geometric factor (calculated by spreadsheet from AB & MN spacings) ∆V = Potential difference measured between MN, in millivolts (mV) I = Current injected at the current electrodes AB, in milliamperes (mA) I'm planning to make another video (when I have time) about field techniques and field sheets & will try to explain this issue in a better way. Have you watched the introduction to resistivity surveys? th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html All the best, Andreas
Hi Daniel please check description below the video. Link to GeoVES Master XLS file: bit.ly/2OpcMvm Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg Link to the video on TH-cam: th-cam.com/video/EN0-Fhan3fs/w-d-xo.html Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html All the best, Andreas
Hi Dr. Laxman Siyol, All the download links are in the description: Link to GeoVES Master XLS file: bit.ly/2OpcMvm Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg All the best, Andreas
Hi Elvis, thanks for a good question but unfortunately the answer is a long one. Please have a look at my video on my recommended groundwater exploration strategy: th-cam.com/video/3c0iPjM65JU/w-d-xo.html The geophysical survey is only one tool in the process, and you need to put it together with all the data from your baseline survey to make the right decision about drill sites and depths. So based on what you know about the area, you can guess what layers are the aquifer and then decide about the drilling. Even the best VES survey is just approximate, so I would always make sure that the drilling rig has the capacity for about 25% extra depth. The decision on drill depth is taken on site during the drilling, so for example you would stop after you have drilled two drill rods into unweathered basement and there are no further water strikes regardless of what the VES has predicted. All the best, Andreas
Hello Andreas, thank you for your video. I am not using commercial equipment, only DC batteries connected in series. How can I measure the current that is being injected into the ground to input into the software?? They are rated for 1.5 Amp-Hours, but not sure what value to input for V / I . Thank you!!!
Hi Loo, As well as your batteries you need both a current meter and a voltmeter to do a resistivity survey. Check out my video on resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html All the best, Andreas
@@GeosearchInternational Thank you very much for your responsiveness and for helping to educate us all, Andreas! I have another few questions regarding how the program generates the dashed blue lines. We see that the error shown in the table is the square of the difference between the data and the model, but what threshold is put on the total error to get the 10% sensitivity range? Going a little deeper, would you be willing to provide the equation that's used to calculate the model from the parameters? Warmest Regards
Hi Loo you are most welcome! The idea of the sensitivity analysis is to see by how much you need to change any of the parameters of the model (resistivity & thickness) in order to get an overall model error which is 10% higher than the error of the original model. All the program does is to increase or decrease the resistivity and thickness of each layer in small increments until the overall model error is 10% higher than the original error. You can manipulate this a bit by deleting any bad data points so that you start off with a lower model error, but the main idea is that if you get overlap between the dashed lines of two layers you should consider modelling it as a single layer rather than two layers. The methodology is based on the linear filters of Gosh (1970). You can see his MSc thesis here: www.researchgate.net/publication/34880203_The_application_of_linear_filter_theory_to_the_direct_interpretation_of_geoelectric_resistivity_measurements All the best, Andreas
If you are interested in spreadsheet models, you should also have a look at the one by Carlos Molano: th-cam.com/video/9QZh688d1lQ/w-d-xo.html Another popular software is IPI2Win: geophys.geol.msu.ru/ipi2win.htm but it is not as transparent as GeoVES for quality control.
@@GeosearchInternational Andreas, am I correct in assuming you used a complicated equation in your model that accounts for multiple subsurface layers? Maybe something to do with boundary conditions? Specifically, I am looking for the equation that takes the given parameters and converts them into an apparent resistivity curve. Would you mind sharing that work? Thank you so much for sharing amazing science!
Hi Salihu, It's all in the description below the video. Link to GeoVES Master XLS file: bit.ly/2OpcMvm Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg Link to the video on TH-cam: th-cam.com/video/EN0-Fhan3fs/w-d-xo.html Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html All the best, Andreas
Hi Naseem, this is a macro-enabled Excel spreadsheet so just download it and follow the methodology as shown in the video. Link to GeoVES Master XLS file: bit.ly/2OpcMvm Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg All the best, Andreas
Hi Zuhair, sorry I don't fully understand your question. In GeoVES we just paste in the field data as deltaV/I, and the AB/2 and the MN spacings. The Geometric factor (K) and the Apparent Resistivity are calculated automatically based on these inputs. All the best, Andreas
Dear Andreas The program is excellent, but it is better if it is using the apparent resistivity (pa) because most modern devices measure the resistance (R)and the apparent resistivity (pa) .All the best Andreas
Hi Zuhair, No device can measure the apparent resistivity. This needs to be calculated from the voltage, current & configuration of the MN & AB spacings (Geometric factor). In my experience so many mistakes are made by the field teams in setting up VES in the field, and on top of that there will be the mistakes in entering the MN & AB spacings so that the device can do the calculations. So, I'm sorry I don't agree with automation of the field survey. I'll make another video when I have some time about the field survey techniques. All the best, Andreas
Hi why can the program don't only accept 2 inputs AB/2 and Rho as other softwares will do ? What is the operator on the field only recorded onle AB/2 and Resistivity? Cheers
Hi Henri, I'm going to make another video soon to explain the field procedures. In the field we record AB/2 and calculate deltaV/I. These are the two inputs, plus MN. GeoVES calculates the resistivity. The advantage is that we can adjust the MN distance to shift the apparent resistivity curve if it is offset from what we think it should be. In the field we also calculate the apparent resistivity and plot the curve on log-log paper in the field. This is very important for quality control. Coming back to your question, I would say that your field operator should record all data, not just the answers. That way you can correct any calculation errors which can easily occur in the field, especially if the weather is very hot or after long field hours. All the best, Andreas
All the links are in the description below the video: Link to GeoVES Master XLS file: bit.ly/2OpcMvm Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg All the best, Andreas
@GeosearchInternational I have another question, please, Mr. Andreas... Do you have any research topics regarding applications of 2D ERT for my master thesis? I appreciate your help... Thanks.
Hi Berham, ERT is quite expensive and time consuming, so usually it is used if you need to get detailed information over a small area. I have used it to map faults & landfills... other applications include archeological sites, graveyards, and areas which will be excavated such as the entrance to tunnels. I would advise that you meet with your local municipality or local companies, and see if any of them have some needs for a detailed imaging of the sub surface. You never know - maybe they can sponsor you as well. Wish you all the best, Andreas
I'm using GeoVES which is an Excel tool with VBA macros doing the calculations. Links are in the description: Link to GeoVES Master XLS file: bit.ly/2OpcMvm Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html All the best, Andreas
Hi Nean, If there is something which is not working for you, please let me know. Unfortunately this spreadsheet is quite complicated, which makes it fragile so I need to keep it protected. All the best, Andreas
@@GeosearchInternational I have saved the master file into a new file for my VES data, however I cannot encode my VES data into it because it is protected. It is asking a password
Hi Sean, You need to enter your data in the green cells only. The rest are protected as they have formulas. Please have another look at the video to see how it works. All the best, Andreas
Hi Rajeev, GeoVES is a groundwater exploration tool which I provide free of charge to anyone who wants to use it. Over the last 20 years it has been checked by many people and I hope that there are no bugs left. It is password protected so that no new errors can get in by mistake. If you do find any bugs, please let me know and I will make an update - for the benefit of all. All the best, Andreas
Hi Dr Suresh, The links are in the description: Link to GeoVES Master XLS file: bit.ly/2OpcMvm Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg It will open in Google Drive - just download & open in Excel. Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html All the best, Andreas
This is such a good explanation of soil resistivity and soil layers. My interest is in the electrical field and earth grid design, this explanation is far easier to understand than the many electrical models I've seen, well done.
Thanks Bryan for your kind words! Much appreciated - you made my day. All the best, Andreas
This is excellent. I've used interpex over the the years. The problem has been the changes made in MN which had distorted the production of excellent curves during iterations . GeoVes has solved that problem. I'll need a link to try GeoVes.
Just look in the description below the video. You can download it from there. All the best, Andreas
It looks very useful - thank you for putting it out there for free. If one has the equipment, it is good to add IP measurements to the sounding as it can resolve some of the equivalence problems but also distinguish between a saline gravel layer and a clay or shale formation. The sortware would have to be modified for chargeability but that is not too difficult using Siegel's formula.
You are welcome George! GeoVES is just a simple tool I developed some 20 years ago in Ghana. You are right - IP is useful, but I don't have much experience with it. I have tried it in Ireland for mineral exploration, but I remember we needed much higher currents than a normal resistivity survey (we almost killed a cow who was eating our cable...) and also special non-polarising potential electrodes. Most of the equipment I have come across in the places where I normally work would not be suitable for this. All the best, Andreas
@@GeosearchInternational There are low-power systems (AGI Sting) which can use IP on multi-cable ERT systems. The larger systems for mineral exploration use higher currents and therefore higher voltages and with gradient arrays they can be dangerous as electrodes might be out of sight. Cattle eating cables is indeed a problem! I'll drop you an email. Regards, George
Hi George! I just got your message - backlog in the TH-cam system... Thanks for your email & nice to be in touch with you! All the best, Andreas
Nice to know that you worked in beautiful agricultural fields of Punjab Pakistan. I am also originally from Punjab and first time I did this type of survey during my Bachelor studies at the University of Agriculture Faisalabad. Thanks for the video
Fieldwork in such a beautiful irrigated area is one of the highlights of the job! I was working on the Lower Bari Road Canal (LBDC) & based in Lahore. The geophysicists in the video did a really great job & had much better data than what many produce with "advanced" resistivity equipment. All the best, Andreas
@@GeosearchInternational where are you based originally? I am really impressed the amount of field work you did. I am modeller and always dream of such a data collection experience in career.
I grew up in Africa & Asia, was educated in UK and then I have been working in over 30 countries in Europe, the Middle East, Africa & Asia. The world is my home. All the best, Andreas
@@GeosearchInternational wonderful. Thanks
Thank you very much. I want to watch your previous videos
Most welcome Ibrahim. Hope you enjoy the other videos! All the best, Andreas
Looking forward to more educational content. Great video.
Thanks Evans! More videos coming soon. All the best, Andreas
Excellent explanation Dear de Jong, very useful video
Thank you Eng. Lalzada! All the best, Andreas
Hello Sir, thanks a lot for putting this video. Hope I will be able to follow this to complete my work and will get the result.
Good luck Pallavi! If you have any questions just let me know. All the best, Andreas
U explain very well. Tqsomuch
Welcome 😊 All the best, Andreas
Excellent explanation
Glad you liked it Santosh! All the best Andreas
Great work. Thank you.
You are welcome Rik! All the best, Andreas
Great work done..! Thanks for sharing your great effort by making such software that is much easy to understand the basics of the VES. Have you develop something similar for the wenner array configration. If yes kindly share that as well. Thanks in advance.
You are most welcome Muhammad! Sorry, I do not use the Wenner array as Schlumberger has many advantages for groundwater exploration. All the best, Andreas
Hi Andreas,
I am trying to create my own inversion software for a university project and I am struggling to calculate an accurate modelled apparent resistivity value when using the inversion model. So far I have managed to find a solution for the forward modelling resistivity transform function of a Schlumberger array to be: Ti(λ) =ρi(1 − e^−2λhj) + Ti+1(1 + e^−2λhj)//ρi(1 + e^−2λhj) + Ti+1(1 − e−^2λhj). Where ρi and hj are the estimated true resistivity and thicknesses for each layer respectively, Ti is the modelled apparent resistivity, and λ is the electrode parameter. I have tried plugging in some of the data used in this video and so far there has been no success! Any help would be greatly appreciated! Thanks :)
Hi Jack,
In GeoVES I used Gosh linear filters. It works quite well for Africa where we have weathered regolith ontop of infinite resistive basement. If the bottom layers have a lower resistivity, Gosh is not optimal. I think O'Neill's filters are better. Please see below a link to his paper:
drive.google.com/file/d/1_9D1drGDKk2BkS1RiPFqD7q4hCFnbBme/view?usp=share_link
Also have a look at the Excel tool made by @MolanoCarlos
th-cam.com/video/9QZh688d1lQ/w-d-xo.html
Good luck & all the best, Andreas
Thank you so much sir...God bless you
Most welcome Asif! All the best, Andreas
Thank you very much!
You are welcome! All the best, Andreas
FELICITACIONES!!!!!!! Una consulta y también tiene modelo para el método de wenner. Saludos desde Perú.
Hola Eriwin, Lo siento, solo funciona con el conjunto de Schlumberger. Un saludo desde Pakistán, Andreas
Hello, sir, thank you for making a data processing tutorial using the Geoves method, now I'm trying to process data using Geoves software, but I have difficulty in the modeling section entering the resistivity value and thickness value because the red line does not merge at the dots
I have difficulty in the modeling section entering the resistivity value and thickness value because the red line does not merge at the dots white circle even though I have entered a value that matches the data. I hope that you will read and reply to my comments Thank you sir
Have you tried fitting a model to the example from the video? If not, try that first. Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg All the best, Andreas
Hello sir
Hope this comment finds you well
Sir, my name is Hidir and I am a geophysics student and I benefit a lot from the educational videos that you publish, so I would like to thank you very much for them.
I have a question that baffles me, and I hope you will answer me if you please.
Question: After we put the data in the excel file and interpreted the VES, how do we determine the locations of groundwater if we do not have information about wells nearby in the area??
Then how can we determine the amount of water that can be extracted from the water-bearing layer of this interpreted section?
waiting for your answer
thank you
Hi Hidir,
Have you seen my video on Groundwater Exploration Strategy, where I try to explain how I normally approach this complex topic? th-cam.com/video/3c0iPjM65JU/w-d-xo.html
Basically, the geophysical survey should come after you have completed a desk study and baseline survey of the project area. That way you can better interpret the VES data. You need to develop a conceptual hydrogeological model first. The VES just helps you to select sites for exploration drilling. e.g. where is the deepest aquifer thickness, or where is the fracture zone.
Once you have a successful well, you need to carry out pumping tests to measure its hydraulic effectiveness (step tests) and how much water you can extract (constant rate & recovery tests). I have made a couple of pumping test videos, but there are still more to come.
All the best, Andreas
@@GeosearchInternationalThank you very much sir.
Welcome! All the best, Andreas
Great video! Congratulations and thank you for sharing. I have a question, is it supposed that MN should be
Hi Gustavo,
You are welcome & glad you liked the video. In the Schlumberger array, the electrode separation AB must be at least 5 times separation MN.
i.e., AB >= 5 * MN
For our first MN separation of 1m, AB should be at least 5m
i.e., MN/2 = 0.5m needs at least AB/2 = 2.5m
OK, so that is the theory. In the field we need to keep things as simple as possible, so that is why we start with MN = 1, and then record AB/2 of 2, 3, 4, 5, 6, 8, 10, 15 m etc. Actually the data should only be valid above AB/2 of 3m, but it does not harm to get a reading before at AB/2 of 2m, so that the field team starts to wake up. I usually discard the first data point anyway as it is often affected by noise/operator error.
In the VES example of the video, the field data was collected in Pakistan by a geophysicist starting with an AB/2 of 1.5, which is maybe a bit too small, and then he misses out some extra measurements I would normally do in order to save some time. He jumps to 3, 5, 7, 10m but the data quality is good, which is what is important.
What I wanted to show with this example is that a guy using a pencil and paper and a really ancient resistivity meter can produce better data than someone with the latest high tech equipment who does not know what he is doing. Geophysics is all about good field techniques, not just pushing buttons. Of course it is important to also keep the theory in your mind & I'm glad you are asking yourself the right questions!
All the best, Andreas
I am using ERT by Schlumberger array. My desired depth of investigation is up to 30m. So please can you tell me how much array length I have to consider so that I can get resistivity up to 30m depth ? It will be a great help. Do i need to take data at different AB,and MN values or can i directly select the one array length with higher spacing AB ?
Hi Suraj, Please see below the field sheets I would normally use for VES.
Schlumberger VES Fieldsheet PDF: bit.ly/3ziyeql2
Schlumberger VES Fieldsheet XLSX: bit.ly/3IXCDT22
Sorry I cannot advise you on ERT. You will need to check the manual. Normally AB needs to be at least three times the depth of investigation but you will need to check with the equipment you are using. I dont understand you question fully, as ERT is normally done using 5 or 10m electrode intervals with multi-core cable. If you are referring to a simple electrical resistivity traverse, the recommended method would be to collect 2 sample points per location. So if you want to explore the 20-30m depth interval you could maybe use AB 100m & AB 60m plus whatever the correct MN is for that.
All the best, Andreas
Hi,, can you prepare a comprehensive video of how a lay man can understand the groundwater potential point in a given area for borewellz and recharge wells ? Tanx fr your valuable videos
Hi @its Me, Glad you like the videos!
Have you seen my video on Groundwater Exploration Strategy, where I try to explain how I normally approach this complex topic? th-cam.com/video/3c0iPjM65JU/w-d-xo.html
All the best, Andreas
This is a very well explained and overall great video! As I am now starting to write my master dissertation about humanitarian geophysics, may I know how can I cite this excel program to my dissertation? Since, I might be using this later in my field test. Thank you. And also does it work for Wenner array configuration too?
Thanks for your kind words Bagoes! I guess you could just link to the video & the file. Something like:
Hydrogeology 101: GeoVES - Free 1D VES inversion for groundwater exploration. Link to the video on TH-cam: th-cam.com/video/EN0-Fhan3fs/w-d-xo.html
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
It is designed for Schlumberger configuration only. I don't recommend Wenner for groundwater exploration, if you want to do VES. All the best, Andreas
Please conduct a webinar. I will be joining.
Hi, good idea but I don't have time at the moment. I hope that you can understand everything from the videos. All the best, Andreas
@@GeosearchInternational Noted. I want to be your student. Soon. Haha
We thank you releasing an important video showing how to analyze electrical resistivity data using excel. I need know difference the excel program an ipi2win software in analysing such data because geophysical survey for groundwater investigation using electrical resistivity method is my undergraduate project. I need to the differences before making decision of which one to use. Thank you.
Best regards.
Hi Salihu, I developed GeoVES 20 years ago because I wanted a program which allowed me better quality control of the data and manual curve fitting. This makes it also a much better teaching tool than other options like the one you mentioned. For your decision the most important consideration is not which program is better, but what your professor thinks who will mark your work. Better you talk with your professor. Alternatively why not try both and find out what the difference is? Good luck and all the best, Andreas
Another important advice is that you should spend even more time thinking about what field procedures you will use to make sure that you collect good data. If the data is not good, no program can fix it later. All the best, Andreas
Ok. Thank you for your advice
Welcome! All the best, Andreas
what is the name of the inversion used in Geoves? is it Damped least square inversion?
GeoVES uses Gosh linear filters. All the best, Andreas
Plz upload some more videos on this VES
Is there anything in particular which you are interested in? All the best, Andreas
Andreas, gratitude for the illustrative teaching. I really enjoyed your explanations using animations in the first and this second video.
What if I only have my AB/2 values, MN values and apparent resistivity values directly from my resistivity meter (tetrameter). How do I use the software to plot or is there a different software?
You're very welcome Ayeni! If you want to use GeoVES, you will need to calculate deltaV/I from the other values, and fill in the data in the green cells of the Data sheet. Alternatively you can maybe try to paste your AB/2 and Apparent resistivity data into the Model sheet, but I have never tried this so not sure if it will work. Let me know if you succeed. All the best, Andreas
Hello Ayeni, we have the same equipment (Abem Terrameter 1000), i also have AB/2, MN/2 and apparent resistivities....did you find a way to use this excel program?
This is wonderful.
Can I send you a resistivity report from a hydrogeologist you advise on it?
Glad you liked it. Sorry I am too busy at the moment. I'm sure that there are competent consultants in your country. All the best, Andreas
Very good.
Thank you! All the best, Andreas
Do you know how to use IPI2win for plotting a graph and combine a 1D to be 2d section? If you know please make a nice video for us.
Sorry I don't use IPI2WIN, I use GeoVES which does everything I need and is much more transparent in how the data is processed.
For 2D sections I use Excel to line up the different geoelectrical models or RES2DINV if there is a lot of data - for example from a resistivity profile. All the best, Andreas
Hello Sir, thanks a lot for putting this video. sir, do you have any of the videos about the VES interpretation?
Hi Abubakkar, sorry I don't have any other videos on VES at the moment. All the best, Andreas
@@GeosearchInternationalsir, you being a hydrogeologist what will be your suggestion about which topic is the best to take as a project in hydrogeology?
@@abubakkarsaddique8909 You mean for a university project? You need to get high marks so best to chose a subject which whoever is marking you likes. Of course you should also enjoy that subject! The most important thing is to have good data, so I would chose the project based on data availability. I would not advise doing any modelling, at least not as the core of the project as many models take a long time to calibrate and you need lots of prior experience to make them work. Good luck and all the best, Andreas
@@GeosearchInternationalCurrently, I have the intention to choose a project as a VES base as I have very much data already available and I want to collect new data and correlate that and plus touch the hydrology little..so I need your view about it?
@@abubakkarsaddique8909 that sounds like an interesting project. All the best, Andreas
please how can I access the free version of the Groves?
Hi Yusuf, the links to the files are always in the description below the video.
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg
Link to the video on TH-cam: th-cam.com/video/EN0-Fhan3fs/w-d-xo.html
Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html
All the best, Andreas
Hello sir, it is really an easy and handy spreadsheet.
However, I want to know how to increase the MN columns in the spreadsheet. As I Have more than 5 MN values ie., 2, 8, 10, 20, 30, 40, 50 in my VES survey.
Hi Neeraj, Adding new MN columns means a redesign of the spreadsheet, so it is not possible. In any case you should not have so many MN changes, as for each change you need to take overlapping readings to correct for any changes in near surface resistivity. I will make a video about this at some stage. Please see below the field sheets I would normally use:
Schlumberger VES Fieldsheet PDF: bit.ly/3ziyeql2
Schlumberger VES Fieldsheet XLSX: bit.ly/3IXCDT22
All the best, Andreas
Thank you sir.
Just wanted to clear my doubt sir.
When am keeping the same V/I values as you have provided in given Punjab sample one, am getting different resistivity values and in graph the points obtained are not in a curve sir.
Kindly correct me if am doing it in a wrong way
Dear Faisal, In the video description I have provided the link to GeoVES example from Punjab: bit.ly/3rQPRXg Download the file by clicking on the down arrow in the top right of the screen.
All the best, Andreas
I can't change for MN and the valua of P resistivty because your resisty data and my resistivty data isnot same so can i get the blank sheet we get it our own data ?
Hi @abdikaniibrahim6091, GeoVES is only for Schlumberger soundings & you need to enter the required data in the green cells, which are: AB/2, MN and deltaV/I. What data does your equipment collect? All the best, Andreas
thanks for sharing, nice job here! ¿is the MN relation definied for the method? i dunno if i'm doing wrong or i just got some terrible data
Hi Andes, I guess you mean the geometric factor (K)? In GeoVES it is fixed for the Schlumberger array, so your data cannot be in other arrays. Please check that you are using the correct MN/2 and AB/2 distances. Good luck and all the best, Andreas
@@GeosearchInternational Dear Andreas, i mean if in the Schlumberger array the MN distance (distance between inner electrodes) is defined like 1, 10, 100 or it can be fixed as more accuracy is required, or if it had to accomplish other condition beside good practices like 'the distance between current electrodes must be at least 5 times the distance between potencial electrodes'. i ask this question because the terrain in which the measures was taken had a lot of rocks buried, and in the graph show a big jump between fixeds MN = 2 and MN = 6 . Thanks in advance
Hi Andes,
Yes, in theory AB should be >=5 x MN.
I usually use MN of 1, 10, 60 & 200m. Basically you only increase the MN distance when you see that the signal is getting weak and you cannot do anything about it like injecting more current, hammering the current electrodes deeper or adding salty water. Then you move up to the next MN distance, but make sure that you have at least 3 overlapping readings with the previous MN distance so you can correct any offsets later on. The data quality depends on how clean your readings are. I always take three separate readings at any location and make sure that they are very similar. If not - hammer electrodes/add water etc... There is no point in averaging the readings as a bad reading will not improve itself. I am planing to make a video about this when I have time. Please have a look at the field sheets below to get a better idea. One last point: always plot your data in the field!
Schlumberger VES Fieldsheet PDF: bit.ly/3ziyeql
Schlumberger VES Fieldsheet XLSX: bit.ly/3IXCDT2
All the best, Andreas
New Question: is the value for deltaV/I similar to deltaAB/MN or is it referring to deltaVoltage/MN?
Hi Nean, ρa = K * ∆V/I,
where
ρa = the Apparent Resistivity (ohm-m)
K = geometric factor (calculated by spreadsheet from AB & MN spacings)
∆V = Potential difference measured between MN, in millivolts (mV)
I = Current injected at the current electrodes AB, in milliamperes (mA)
I'm planning to make another video (when I have time) about field techniques and field sheets & will try to explain this issue in a better way.
Have you watched the introduction to resistivity surveys?
th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html
All the best, Andreas
How do I get the software sir. Thanks for the wonderful lecture
Hi Daniel please check description below the video.
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg
Link to the video on TH-cam: th-cam.com/video/EN0-Fhan3fs/w-d-xo.html
Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html
All the best, Andreas
sir please share Downloading link of Geo VES software
Hi Dr. Laxman Siyol, All the download links are in the description:
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg
All the best, Andreas
How do I then inteprete these results? And how does it guide me in selecting a good depth for the borehole and the sitting of the borehole
Hi Elvis, thanks for a good question but unfortunately the answer is a long one. Please have a look at my video on my recommended groundwater exploration strategy: th-cam.com/video/3c0iPjM65JU/w-d-xo.html The geophysical survey is only one tool in the process, and you need to put it together with all the data from your baseline survey to make the right decision about drill sites and depths. So based on what you know about the area, you can guess what layers are the aquifer and then decide about the drilling. Even the best VES survey is just approximate, so I would always make sure that the drilling rig has the capacity for about 25% extra depth. The decision on drill depth is taken on site during the drilling, so for example you would stop after you have drilled two drill rods into unweathered basement and there are no further water strikes regardless of what the VES has predicted. All the best, Andreas
Very interesting,
How can I have this GeoVes.
Hi @chilofra818, please look in the description below the video for links to all tools. All the best, Andreas
Hello Andreas, thank you for your video. I am not using commercial equipment, only DC batteries connected in series. How can I measure the current that is being injected into the ground to input into the software?? They are rated for 1.5 Amp-Hours, but not sure what value to input for V / I . Thank you!!!
Hi Loo, As well as your batteries you need both a current meter and a voltmeter to do a resistivity survey. Check out my video on resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html
All the best, Andreas
@@GeosearchInternational Thank you very much for your responsiveness and for helping to educate us all, Andreas!
I have another few questions regarding how the program generates the dashed blue lines.
We see that the error shown in the table is the square of the difference between the data and the model, but what threshold is put on the total error to get the 10% sensitivity range?
Going a little deeper, would you be willing to provide the equation that's used to calculate the model from the parameters?
Warmest Regards
Hi Loo you are most welcome!
The idea of the sensitivity analysis is to see by how much you need to change any of the parameters of the model (resistivity & thickness) in order to get an overall model error which is 10% higher than the error of the original model. All the program does is to increase or decrease the resistivity and thickness of each layer in small increments until the overall model error is 10% higher than the original error. You can manipulate this a bit by deleting any bad data points so that you start off with a lower model error, but the main idea is that if you get overlap between the dashed lines of two layers you should consider modelling it as a single layer rather than two layers.
The methodology is based on the linear filters of Gosh (1970). You can see his MSc thesis here: www.researchgate.net/publication/34880203_The_application_of_linear_filter_theory_to_the_direct_interpretation_of_geoelectric_resistivity_measurements
All the best, Andreas
If you are interested in spreadsheet models, you should also have a look at the one by Carlos Molano: th-cam.com/video/9QZh688d1lQ/w-d-xo.html
Another popular software is IPI2Win: geophys.geol.msu.ru/ipi2win.htm but it is not as transparent as GeoVES for quality control.
@@GeosearchInternational Andreas, am I correct in assuming you used a complicated equation in your model that accounts for multiple subsurface layers? Maybe something to do with boundary conditions?
Specifically, I am looking for the equation that takes the given parameters and converts them into an apparent resistivity curve.
Would you mind sharing that work?
Thank you so much for sharing amazing science!
Thanks!
Thanks so much Loo! All the best, Andreas
Hi, I'd like to ask, can this be used in the Wenner array?
Sorry, no it is just for Schlumberger. All the best, Andreas
Hi! how can I get this geoves program
Hi Salihu, It's all in the description below the video.
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg
Link to the video on TH-cam: th-cam.com/video/EN0-Fhan3fs/w-d-xo.html
Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html
All the best, Andreas
Hello Sir how can i install this software
Hi Naseem, this is a macro-enabled Excel spreadsheet so just download it and follow the methodology as shown in the video.
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg
All the best, Andreas
hi Andreas, Thanks a lot. my question why her (MN-1 MN-2 MN-3----) its called the geometric parameter (K)
and not MN
Hi Zuhair, sorry I don't fully understand your question. In GeoVES we just paste in the field data as deltaV/I, and the AB/2 and the MN spacings. The Geometric factor (K) and the Apparent Resistivity are calculated automatically based on these inputs. All the best, Andreas
Dear Andreas The program is excellent, but it is better if it is using the apparent resistivity (pa) because most modern devices measure the resistance (R)and the apparent resistivity (pa) .All the best Andreas
Hi Zuhair, No device can measure the apparent resistivity. This needs to be calculated from the voltage, current & configuration of the MN & AB spacings (Geometric factor). In my experience so many mistakes are made by the field teams in setting up VES in the field, and on top of that there will be the mistakes in entering the MN & AB spacings so that the device can do the calculations. So, I'm sorry I don't agree with automation of the field survey. I'll make another video when I have some time about the field survey techniques. All the best, Andreas
Hi
why can the program don't only accept 2 inputs AB/2 and Rho as other softwares will do ? What is the operator on the field only recorded onle AB/2 and Resistivity?
Cheers
Hi Henri, I'm going to make another video soon to explain the field procedures. In the field we record AB/2 and calculate deltaV/I. These are the two inputs, plus MN. GeoVES calculates the resistivity. The advantage is that we can adjust the MN distance to shift the apparent resistivity curve if it is offset from what we think it should be.
In the field we also calculate the apparent resistivity and plot the curve on log-log paper in the field. This is very important for quality control. Coming back to your question, I would say that your field operator should record all data, not just the answers. That way you can correct any calculation errors which can easily occur in the field, especially if the weather is very hot or after long field hours. All the best, Andreas
How I download it
All the links are in the description below the video:
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg All the best, Andreas
Is it compatible with Windows 11?
Thanks.
Hi Berham, yes it works but you need to leave the file in its original XLS format. Do not save it in XLSX or XLSM format. All the best, Andreas
@@GeosearchInternational Thank you so much
@GeosearchInternational
I have another question, please, Mr. Andreas...
Do you have any research topics regarding applications of 2D ERT for my master thesis?
I appreciate your help...
Thanks.
Hi Berham, ERT is quite expensive and time consuming, so usually it is used if you need to get detailed information over a small area. I have used it to map faults & landfills... other applications include archeological sites, graveyards, and areas which will be excavated such as the entrance to tunnels. I would advise that you meet with your local municipality or local companies, and see if any of them have some needs for a detailed imaging of the sub surface. You never know - maybe they can sponsor you as well. Wish you all the best, Andreas
@GeosearchInternational The insights you provided are very useful... thanks again.
Hi sir, what software do u use for plotting VES. How can i download it. Plz help me regarding
I'm using GeoVES which is an Excel tool with VBA macros doing the calculations. Links are in the description:
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg
Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html
All the best, Andreas
How can I unlock the Free VES excl file?
Hi Nean, If there is something which is not working for you, please let me know. Unfortunately this spreadsheet is quite complicated, which makes it fragile so I need to keep it protected. All the best, Andreas
@@GeosearchInternational I have saved the master file into a new file for my VES data, however I cannot encode my VES data into it because it is protected. It is asking a password
Hi Sean, You need to enter your data in the green cells only. The rest are protected as they have formulas. Please have another look at the video to see how it works. All the best, Andreas
@@GeosearchInternational Thank you!
Welcome! All the best, Andreas
it is sheet protected. Can you please provide unprotect sheet password?
Hi Rajeev, GeoVES is a groundwater exploration tool which I provide free of charge to anyone who wants to use it. Over the last 20 years it has been checked by many people and I hope that there are no bugs left. It is password protected so that no new errors can get in by mistake. If you do find any bugs, please let me know and I will make an update - for the benefit of all. All the best, Andreas
@@GeosearchInternational Thanks for your reply
@@rajeevkrishnan5241 you are welcome! All the best, Andreas
Great sir, from where I shall get free geo ves 1d software . ,?
Hi Dr Suresh,
The links are in the description:
Link to GeoVES Master XLS file: bit.ly/2OpcMvm
Link to GeoVES example from Punjab discussed in the video: bit.ly/3rQPRXg
It will open in Google Drive - just download & open in Excel.
Link to a TH-cam video on introduction to resistivity surveys: th-cam.com/video/MvOR4xY1Mb8/w-d-xo.html
All the best, Andreas
Any link for download this software?
Dear Saheb, please have a look in the description under the video for links to the files. All the best, Andreas
@@GeosearchInternational Thanks a lot. It will help me a lot in my research work.
You are welcome & good luck with your research! All the best, Andreas
Thank you so much!
You're welcome! All the best, Andreas