Single and Multibeam Bathymetry grids of the Gippsland Basin - 100 and 50m resolution - 2013

Brief description

The compilation and processing of GA's single and multibeam bathymetry data in the Gippsland Basin was produced following a request by an internal client in November 2013.
It is an updated version of the 2012 bathymetry grid of the Gippsland basin.

Lineage

Maintenance and Update Frequency: asNeeded

Statement: - Grid resolution: 50 and 100m
- Number of grids: 2
- Total surface coverage: 32,287.53 km2
- Vertical Datum: MSL
- Horizontal Datum: WGS84 UTM-55S
- Use Limitation: This dataset is not to be used for navigational purposes.

This dataset was compiled and processed in GA by Michele Spinoccia, using CARIS HIPS & SIPS ver 7.1.2.
1. First a vessel configuration file was created for each vessel 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 artifacts.
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-55S.
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 artifacts 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.
In GA the tide was applied to the grid to correct for tidal variations and velocity corrections were performed to correct for different artifacts and mismatches.
9. The processed data was finally exported as grids soundings or false coloured images for presentation and reporting and as final processed data in in ASCII XYZ as well as geotif formats of 50 and 100m resolution.
10-Using CARIS Base editor 4.0 the grids were exported as ESRI ASCII grid, then imported into ARC catalogue/info to create a raster file for the entire survey.