Auto Level implements two different methods for recongizing the first signal in GPR traces/scans and lines them all up vertically according to amplitudes and their time of arrival. This levels out the top of profiles and corrects for drift or variations in the surface wave due to ground conditions. In many cases the improvement is seen in slice maps by removal of some striping, especially in shallow slices.

 

Method A usually works best, and uses a higher threshold for recognizing the first wavelet.

 

Method B works better for higher amplitude data.

 

In many cases this step can be skipped by checking the Skip box in the upper-right.