Video: Resistivity mapping introduction 
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In this video we introduce the resistivity method as an active survey type which probes the sub-surface in terms of its electrical resistivity. We derive a solution for the current flow density in a homogenous halfspace and then visualize the potential field for a two electrode setup. The need for a four electrode setup is explained.


.. image:: VidResistivity1.png
  :target: https://www.youtube.com/watch?v=5KgupS8gdts&t=508s
  :width: 400
  :alt: Principle of 4 point resistivity mapping

Next we explore the possibility to map a lateral homogenous (vertically variable) sub-surface using the principal of vertical electrical sounding:

Video: Principle of vertical eletrical sounding 
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Next we explore the possibility to map a lateral homogenous (vertically variable) sub-surface using the principal of vertical electrical sounding:
.. image:: VidResistivity2.png
  :target: https://www.youtube.com/watch?v=l2-sxg65KUE&t=955s
  :width: 400
  :alt: Vertical eletrical sounding