Airborne Laser Scanning (ALS) Data Across The Wet Tropics of Queensland, 2024 

This data contains Airborne Lidar Scans data that were acquired on 14 permanent plots in far North Queensland, during August – September 2024. This dataset contains the georeferenced, noise-classified and tiled point clouds for 14 ROIs covering these plots. The data are stored in LAS v1.4 files compressed using laszip. 

We at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging.  

• The many traditional owner groups who are custodians of these lands.
• Queensland Parks and Wildlife service for assistance in permitting.
• Wet Tropics Management Authority for assistance at Robson Creek.
• James Cook University staff for assistance at the Daintree Rainforest Observatory
• Dr Geoff Stocker for establishing the QPRP-CSIRO plots (EP codes), funding and administration support of CSIRO, and census work by CSIRO staff and many volunteers.
• Joseph H Connell for establishment and long-term custodianship of DAV. 

 

Large-scale estimation of aboveground biomass across the Wet Tropics of Queensland for calibration and validation of Earth observation data. 

Acquisition:

These data were collected using a RIEGL VUX-120 and Trimble Applanix APX-20 GNSS/INS kinematic laser scanning system mounted on a Bell 407 helicopter, targeting a 127 m spaced parallel line configuration at 28.3 m/s velocity with an aboveground level of 160 m. This configuration targeted a point density > 230 pts/m2. The instrument pulse repetition rate, field of view and scan rate were 1200 khz, 100 degrees and 400 lines per second, respectively. The laser pulse had a wavelength, pulse width, beam divergence and exit footprint diameter of 1550 nm, 3.0 ns, 0.38 mrad and 5.7 mm, respectively. A nearby static Stonex S900A GNSS receiver collected observables throughout data acquisition for georeferencing purposes.

Processing:

Airborne mission trajectories were refined to survey-grade accuracy and precision via Applanix POSPac UAV (v9.1) using GNSS observables from the base station, whose absolute positioning was refined using the AUSPOS service. Lidar data were united with these trajectories and merged into georeferenced tiled point clouds using RIEGL RiPROCESS (v1.9.5) and its RiUNITE (v1.0.9.3) and RiPRECISION modules. Noise was labelled using reflectance and deviation thresholding, and statistical outlier filtering.

File format:

The data are stored in LAS v1.4 files compressed using laszip (see file metadata for specifics). The coordinate reference system is WGS 84 UTM 55S (EPSG: 32755). Tile sizes are 100 x 100 m2. The naming convention follows [syl_uid]_[roi_id]_[tile_x]_[tile_y].laz e.g., 0013AU_BAL_333400_8085100.laz, whereby syl_id and roid_id represent a Sylvera unique field campaign identifier and region of interest identifier (see table above), respectively. tile_x and tile_y refer to the x-y origin of the tile with respect to the CRS. The extra bytes functionality provided by the LAS specification is used to conserve REIEGL-specific records (e.g., Reflectance and Deviation).