Figure 2. Diver demonstrates DRR methodology with inset showing level gauge.

Digital Rugosity measurements are accomplished by using the instrument as a plumb-bob to slowly follow the contour of the reef as closely as possible. The pressure transducer is located near the end of the instrument closest to the substrate. The recorded pressure depth is offset from the actual reef substrate depth by the distance between the transducer and the substrate (photo A Alling).