Forster Pacific Palms Cape Hawke, NSW Backscatter 2019 (20190159S)

Full description

The Forster Pacific Palms Cape Hawke, NSW, multibeam survey was acquired by the NSW government (Department of Planning and Environment – DPE) onboard the Research Vessel Bombora during the period 01/MAR/2019 – 12/AUG/2022, using DPE’s R2Sonic 2022 multibeam sonar. The survey was completed as part of the SeabedNSW program funded by NSW government through Coastal Reforms (>2015), HabMap Program funded through Marine Parks Authority (now under Marine Estate Management Authority) or through collaborations with partner agencies or institutions. The purpose of the project was to 1) provide a baseline dataset and 2) map the spatial distribution of seabed types. This dataset contains 32-bit floating point geotiff files of bathymetry and backscatter in 5m resolution for the study area, derived from the processed Hypack, R2Sonic GUI, POSView, POSPac, Qimera and FMGT software. General details on vessel setup, mobilisation and processing are provided at https://www.environment.nsw.gov.au/-/media/OEH/Corporate-Site/Documents/Research/Our-science-and-research/seabed-nsw-standard-operating-procedures-multibeam-surveying-190101.pdf with survey specific details in the Survey Report and DPIE Rigor Statement.

Not to be used for navigational purposes

Lineage

Maintenance and Update Frequency: asNeeded

Statement: AusSeabed follows the recommended processing methodology as prescribed by the AusSeabed Multibeam Guidelines (https://australian-multibeam-guidelines.github.io/). Please note that certain products are subject to routine update (e.g. resolution, coverage, temporal variation, guidelines/best practice). The client is advised to refer to the latest version of all documents and products for the mostup-to-date material. For eCat records the version is expressed in the record title whilst products incorporate date of production as per AusSeabed’s file naming convention. The bathymetry dataset was produced using QPS Qimera and the AusSeabed-recommended processing methodology as follows: 1. A new QPS Qimera project was created in conjunction with existing or newly created vessel configuration file(s). 2. The raw swath sonar data files were imported to the project. G2 Marine Star provides the navigation and ellipsoid height source and is recorded in POSView and post-processed in POSPac for a Smoothed Best Estimate of Trajectory (SBET) using the Single-Base Station module. 3. The POSMV data files were imported to the project to bring in delayed heave, delayed heave RMS, ellipsoid height and ellipsoid height RMS. 4. TPU and GPS tide were computed and all data were georeferenced (merged) to AHD using the ellipsoid AusGeoid09 model. 5. An auto-resolution CUBE was generated as a reference surface for data cleaning. 6. An automated data cleaning using the surface cleaning method with the reference surface was undertaken. 7. Further manual cleaning was conducted as required after visual assessment. 8. The final grid was produced at 5m resolution. 9. At Geoscience Australia, the received geotiff was shifted to EGM2008 using AusCoastVDT and CARIS HIPS and SIPS. 10. The final processed grids were exported as a 32-bit floating point Geotiff at 5m resolution, referenced to EGM2008. The backscatter dataset was produced using QPS Qimera and FMGT software and the AusSeabed-recommended processing methodology as follows. 1. R2Sonic ‘true-pix’ amplitude and ‘snippets’ time-series were treated separately. Truepix files were exported as GSF from Hypack using MBMAX and then imported into a new QPS FMGT project. R2Sonic ‘snippets’ (time-series) paired files were imported into a separate QPS FMGT project and processed using the ‘time-series’ functionality. 2. A cleaned bathymetry DEM was also imported into each of the FMGT projects. 3. For each QPS FMGT project processing options were adjusted within the Processing Parameters tab as follows: Transmit/receive, Power Gain Correction and Apply Beam Pattern Correction were selected and a 60⁰ beam angle cut-off applied. 4. For the Sonar Defaults tab, system options are set to automatic and R2Sonic 2022 sonar type selected. Surface Sound Speed is set to 1520 metres/second and Angle Varied Gain set to ‘Trend’ with a default window size of 300. All other parameters are left as default. 5. Mosaics are generated at 5m grid scale either as a single mosaic or as tiles, depending on file size with the cleaned bathy surface activated. 6. The backscatter adjustment function was used to adjust line brightness for individual transects to provide a more uniform mosaic. 7. Once completed mosaics were exported as geotiffs and XYA from each project in grid co-ordinates WGS84 56S. 8. The final processed grid was exported as a 32-bit floating point Geotiff at 5m resolution.

Notes

Purpose
To derive seabed information for the purpose of supporting the sustainable use of our marine environment and jurisdiction; strengthening our resilience to natural hazards and enabling location-based decisions and actions through best practice digital mapping, Earth observations and precise positioning.