One popular survey type which was made possible by multi electrode instruments is the 2D profile. For a 2D profile data is collected using a multi electrode system over an array of generally equidistantly spaced electrodes laid out along a straight line on the surface. This configuration remains one of the most popular ones used to date. The reasons for this popularity are threefold:
Associated with 2D profiles is a choice of how to collect data (the so called acquisition geometry). The acquisition geometry describes the relative position of the current and potential electrodes. It is clear that as we increase the number of electrodes the number of possible ways we can collect data increases rapidly. Different standard acquisition geometries have been developed over the years which are generally believed to provide reasonable quality data. An overview of the most commonly used geometries is given here. Specific acquisition geometries are selected for three reasons:
There are multiple papers and studies which discuss the sensitivity of different array types and the respective value of different arrays. This includes e.g a a paper in Vadose Zone Journal by Furman et al (note that a pdf of this paper can be found on the internet through google scholar) and the course notes from Loke on resistivity imaging.