Figure 8. Example of a raw GLORIA data file. Each line of this 6-hour-long GLORIA pass contains a 30-second swath, 924 pixels wide, and 720 lines in length. The first 32 bytes of each line is the swath header information and contains the date, time, and position of the swath and depth. The image illustrates the water-column offset produced by the distance the sonar vehicle is towed above the seafloor (Twichell, 1988).