Davis Coast Bathymetry Survey 2017

Brief description

Geoscience Australia conducted a hydrographic and seafloor characterisation survey nearshore from Davis Station in the Australian Antarctic Territory. The multibeam bathymetry data was acquired during January-February 2017 from the AAD workboat Howard Burton in the Vestfold Hills region. This survey is a component of the Australian Antarctic Program (AAP) and Project 5093 Hydrographic Surveying and Seafloor Characterisation Program (Chief Investigator: Ursula Harris, AAD). The objective of the survey was to map the seabed environment in shallow (<300 m) coastal waters for the compilation of nautical charts and acquire baseline data for environmental management, science, infrastructure and logistical operations. Data collected during the survey includes high-resolution multibeam bathymetry, backscatter, sediment samples, seafloor imagery and sub-bottom profiles. This dataset is a 32bit geotiff at 11 m resolution using EGM2008 vertical datum and EPSG:4326 coordinate system and produced from the processed EM3002D/ EM2040C Dual system bathymetry data. This dataset is published with the permission of the CEO, Geoscience Australia. Not to be used for navigational purposes.

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Maintenance and Update Frequency: asNeeded

Statement: The survey data was acquired by Geoscience Australia using the Australian Antarctic Division workboat Howard Burton 10 January to 6 February 2017 as a component of Australian Antarctic Program (AAP) Project 5093 Hydrographic Surveying and Seafloor Characterisation Program.
The Chief Scientist onboard the Howard Burton was Dr. Jodie Smith (Geoscience Australia) and the Officer in Charge of Survey onboard the Wyatt Earp was LCDR MI Kumpis (Deployable Geospatial Support Team, DGST). Initial processing of the datasets was conducted during the survey by Kim Picard (Geoscience Australia), POHSM PJ Coates and LCDR MI Kumpis (DGST). The high-resolution bathymetry grid (2 m resolution) was produced following final processing by Michele Spinoccia (Geoscience Australia), using CARIS HIPS & SIPS ver 7.1.2 and 9.1.12. The 32bit Geotiff provided here was processed by Christopher Yule (Geoscience Australia) using CARIS HIPS & SIPS ver 11.3.

Processing methodology:
1. First a vessel configuration file was created where the co-ordinates of the motion sensor and DGPS antenna and patch test offsets were recorded.
2. A new project was then created and the vessel configuration file was attached to the project file.
3. The raw swath sonar data, for each line was then imported into the project and the vessel information assigned to the data.
4. The motion sensor, DGPS and heading data were then cleaned using a filter that averaged adjacent data to remove artefacts.
5. Different sound velocity profiles data for each block were attached to the corresponding raw swath sonar data files to correct the depths for changes in the speed of sound through the water column.
6. Then a new blank field area was defined that specified the geographic area of study and the co-ordinate system used. The co-ordinates for the study areas were WGS84 UTM-43S.
7. The data was cleaned by applying several filters that removed any remaining spikes in the bathymetry data using user defined threshold values. A visual inspection of the data for each line was then undertaken where artefacts and noisy data not removed by the filtering process were removed manually using Swath and subset editors modules of the Caris HIPS/SIPS software.
8. All the data for each bathymetric, motion sensor, DGPS, heading, tide and sound velocity profile data were merged to produce the final processed data file. A weighted grid of the processed data was then created for each Block.
9. The processed data was finally exported as gridded sounding or false coloured images for presentation and reporting and as final processed data in ASCII XYZ as well as geotif formats at the optimum resolution the data can provide.
10. Using CARIS HIPS & SIPS 9.1.12 the grid was exported as ESRI ASCII grid, then imported into ARC catalogue/info to create a raster file for the entire survey in a 2m resolution grid.
11. Hips file created from steps 1-10 was opened into CARIS HIPS & SIPS 11.3 to import all survey lines and an 11 m resolution, regular gridded surface was created.
12. The final processed grid was exported as a 32 bit Geotif format at 11 m resolution georeferenced to EGM2008 vertical datum and EPSG:4326 coordinate system.

Notes

Purpose
Bathymetry Survey