DC2DInvRes - Data Menu

Estimate Error

Knowing the accuracy of the data points can significantly increase the interpretation of geophysical data. If errors (in terms of standard deviations) are not measured, it is possible to estimate. The (relative) data erros are supposed to consist of three parts, a percentage error plus an voltage error considering the limited accuracy of the field equipment plus errors due to varying electrode positions.
The voltage error is divided by the driving current and multiplicated by the configuration factor giving large errors for high k-values (such as dipole-dipole) and small errors for low k-values (such as wenner).
If no errors are given in the data file, an error estimation dialog is called. It is also possible to assume equal errors for the data or to read the standard deviation from text file.

 

Edit Data

The Edit Data GUI can be used for prepocessing data. The data can be selected according the relations >,< and = to a defined quantity of the following fields:

  • apparent resistivity
  • error estimate
  • electrode position (any of them)
  • configuration factor k
  • IP data (if present)
  • current I (if present)
  • voltage U (if present)

The button "find&show" shows the found data with red, the others are blue.
The "Statistics" button provides a histogram of the selected field.
By clicking on "Delete" the selected (red) data points are deleted from the data set.
"Show" displays the selected field, and "Close" exits the GUI.

Create data set

For modelling studies, it is possible to create data sets with the following dialog.
The number of electrodes are required as well as the position of the first electrode and the electrode spacing. Surface arrangements (Wenner, Schlumberger, Pole-Pole, Pole-Dipole, Dipole-Dipole), surface-to-borehole and cross-borehole measurements can be simulated using the Create and Add button and viewed by the show button.

Write Data

The data are saved in the above described format (including errors).

Hotkey: Shift+W

Export Data

The data are exported in RES2DINV format using the arbitrary electrode position feature (type=11).

Hotkey: Shift+E

Forward Calculation

Sometimes (e.g. when interactively modelling) it is useful to call forward calculation manually. The resulting forward response is displayed.

Hotkey: Shift+F

Add noise

When creating synthetic data, it is realistic to add random errors to the data (using standard deviations).

Set forward calc as data

This options sets the data to the values of the forward response.