• Target must be characterized by a resistivity contrast
• Buried wires, metal pipes, metal fences influence measurements
• Urban areas may cause high noise levels (e.g., stray currents)
• In some areas electrode coupling may be poor (e.g. asphalt, gravel)
• Measurements during rain should be avoided

Typical depth of investigation ranges from less than a meter to several tens of meters.

• Measured parameter: Voltages [mV]. Depending on electrode configurations and currents injected values may range from a few µV to several V.
• Data analysis: Voltages are plotted in form of apparent resistivities as profiles or contour maps.
• Interpretation: Often qualitative. Areas displaying anomalously high or low values, or anomalous patterns can be identified. Depth of objects can be roughly estimated. Additional geological or geophysical surface data may be required for reliable interpretation. A priori information (layer thickness and / or resistivity values) are helpful to constrain the models.

• Required additional information: rough estimates of target depths
• Related add-on information: electromagnetic data
• Independent additional information: georadar data ; seismics data

• Crew size: 1 key person, 1-2 assistants
• Acquisition speed: Small arrays (< 100 m): 300 - 400 measurements per day; large arrays (> 100 m): 250 - 400 measurements per day (with new, automated data acquisition systems these numbers may be increased substantially).
• Processing: requires 1 day per acquisition day
• Equipment rental costs: intermediate

• Array type: Usually Wenner- or Schlumberger-type arrays are employed.
• Array size: Total length of array: 3 to 10 times the depth of investigation; typically more then six times the depth of investigation
• Array orientation: Should be perpendicular to the strike for a maximum response of geological structures (if only measured along profiles)
• Electrode spacing: Usually between 1 and 10 m

• Documentation of accuracy of transmitted currents and voltages
• Measurements of natural potentials and transition resistances between electrodes and ground
• Measurements of reproducibility (measurements of reciprocal or redundant configurations)
• Optional: Map of buried cables

• Line graphs or contour plots of apparent resistivities
• Profile data
• Interpretation