Figure 9. Light detection and ranging (lidar) interpretation method: example from three inset flows at river mile 188. The Colorado River is flowing to the south. (A) Top and bottom of each flow is digitized based on 0.3 m resolution near-infrared aerial photographs. The digitized top and bottom are shown as black lines. (B) Grid of slope (derived from lidar) is overlaid over the aerial photographs. Pink areas denote cliffs where the slope is over 75°. Lidar data are then used to calculate top and bottom elevations for each remnant along its length. The data from Figure 9 are shown as three inset flow remnants of different ages on Figure 10 at river mile 188: Whitmore (green), Black Ledge (Orange), and Gray Ledge (blue). Shown in purple is the Whitmore Cascade, which is interpreted to overlie the Whitmore flow locally.