Calculated from the measured 

(2)
(2)
In symmetric electroprofiling with four electrodes, a device is used, and during observations, it is moved from picket to picket in a row without changing the distances between these electrodes, and the value is measured. The values of calculated from the measured  values are determined along the profile.
Relative electrical resistance is the resistance to electric current passing from one edge to the opposite edge of a cubic body with a side equal to one meter. , from which here, R - resistance; -the length of the conductor; S is the cross-sectional area of the conductor.
The specific electrical resistance of different rocks varies in a very wide range: from 0.001 Ohm to 1015 Ohm in pure metals.