IZIFLAT is a post-processor utility which analyzes all the VB sightlines using information from a given SNAP try and determines the VB signal if , the so-called VBZ=1 signal for each sightline. The program can further read the SH raw data file and get the signals for each channel for the shot at the time. The can be assumed flat, in which case the relative calibration factors (efficiencies) can be determined for each channel. Or efficiencies can be input and the line-integrated as a function of impact radius can be plotted, to test whether the assumption of a flat profile is justified.