LiDAR scans were taken using a tripod mounted Riegl VZ-400 scanning LiDAR. The tripod was set up such that the scanner was between 1 and 2.5 m tall. The VZ-400 is a near infrared (1550 nm) scanner. Geometric control was achieved, when the sky was visible, using a pair of Trimble RB GPS antennae, one mounted on the LiDAR scanner (rover) and the other setup as a base station. Before taking a LiDAR scan, the VZ-400 would use the GPSs to fix a real time kinematic (RTK) solution for the scanner’s location and then use that position (scan position) as a reference for LiDAR returns. Scans from inside the cave were linked to outside scans in post processing. Post processing was done using RIScan-Pro version 2 (scanner specific software). Also, in post-processing, overlapping areas of point clouds were merged and mismatches in roll, pitch and yaw, were resolved using a multi station adjustment routine. The data were projected in UTM coordinates for export. Once post-processed, data were exported in “.las” format with LiDAR reflectance (infrared) saved as intensity. The point clouds are georeferenced and projected in UTM Zone 10 North and generally have < 1 cm point spacing (unless otherwise noted in file name, see below), however spacing varies locally and depending on the distance from the scanner to the target and data shadows produced by surface roughness and laser occultations.
