Vertical Electrical Sounding

[ferryatm]

datatest.xlsx

Please help me, I'm new to this and really want to learn pygimli for VES. I have Schlumberger VES field data, can you make me a 1D VES inversion code? like starting from synthetic data and then calling up the field data that I have in Excel. I plan to compare the results with the curves in IPI2Win and Res1Dinv. Please help me just this once :(

[halbmy]

Please have a look at the tutorial https://www.pygimli.org/_tutorials_auto/3_inversion/plot_2-dc1dblock.html

I created a script

import pandas as pd
import matplotlib.pyplot as plt
import pygimli as pg
from pygimli.physics.ves import VESModelling
from pygimli.frameworks import MarquardtInversion
from pygimli.viewer.mpl import drawModel1D

data = pd.read_excel("datatest.xlsx")
fop = VESModelling(ab2=data["AB/2 (m)"],
                   mn2=data["MN/2 (m)"],
                   nLayers=2)
inv = MarquardtInversion(fop=fop, verbose=True)

rhoa = data["Rho (Ohm.m)"].values  # pandas->numpy
model = inv.run(rhoa, relativeError=0.05, verbose=True)

fig, ax = plt.subplots(ncols=2)
ax[0].loglog(rhoa, ab2, "x", label="data")
ax[0].loglog(inv.response, ab2, "-", label="response")
ax[0].invert_yaxis()
ax[0].legend()
ax[0].grid()
drawModel1D(model=model, ax=ax[1])

[ferryatm]

Why do the resistivity and depth graphs in the tutorial have two orange and blue curves? sorry, I still have a lot to learn

[ferryatm]

and can the inversion use Gauss-Newton method?

[halbmy]

Yes, the inversion uses a Gauss-Newton method by default.

[halbmy]

The blue crosses are the measured (or synthetic modelled) data and the orange line is the model response. In case of a synthetic experiment, one can plot both the synthetic (blue) along with the inverted (orange) model. A label is missing here. Please read the tutorial in detail and give feedback which part is not sufficiently explained.

[ferryatm]

sorry if I ask again, but this seems a bit complex and not in the tutorial. I mean how do you make a curve like this? by comparing pyGIMLi IPI2win and Res1Dinv in one curve based on the field data that I have? that's all actually, I'm just a little confused

[halbmy]

I don't get your question. The code for plotting both model and data was pasted above and there is also the tutorial where several curves are plotted in one axis. Can you specify your problem in detail.

[ferryatm]

Sorry in advance if it's confusing. So in essence, IPI2win and Res1Dinv are two conventional software that are often used for VES inversion. I want to compare the two software with PyGIMLi (open source which prioritizes flexibility), to see whether PyGIMLi is accurate or not when implementing the field data that I have. More or less like that, I want to introduce PyGIMLi to my campus through this. I mean, can the curves produced by IPI2win, Res1Dinv, and PyGIMLi be combined in one graph to make it easier to compare them? Once again, sorry if it's confusing 🙏

[halbmy]

We'd be happy if you introduce pyGIMLi on your campus. If you have the model vectors for all four models (synthetic and the three softwares) in the form of N-1 thicknesses followed by N resistivity values, you can plot them all just like in the tutorial.

fig, ax = plt.subplots()
ves.showModel(synthModel, ax=ax, label="synth")
ves.showModel(ipi2winmodel, ax=ax, label="IPI2Win")
ves.showModel(res2dinvmodel, ax=ax, label="Res1dInv")
ves.showModel(ves.model, ax=ax, label="pyGIMLi")
ax.legend()