The grids were compiled from the following surveys:

# Survey Name Vessel Name Multibeam System Institution Start Date End Date Start Port End Port

1- GA-1154_BMRG06MV RV_Melville SeaBeam 2000 (12 kHz) SCRIPPS 22/2/1996 15/04/1996 Fremantle Port Hedland

2- GA-1166_WEST09MV RV_Melville SeaBeam 2000 (12 kHz) SCRIPPS 10/12/1994 22/01/1995 Fremantle Fremantle

3- GA-1274_SIO WEST10MV RV_Melville SeaBeam 2000 (12 kHz) SCRIPPS 29/1/1995 12/3/1995 Fremantle Hobart

4- GA-2305_EW0114 RV_Maurice_Ewing Atlas HydrosweepDS (12 kHz) LDEO 07/12/2001 24/02/2002 Fremantle Hobart

5- GA-2309_MR03K04Leg6 RV_MIRAI SeaBeam 2112 (12 kHz) JAMSTEC 27/01/2004 19/02/2004 Fremantle Fremantle

6- GA-2389_NBP0406 RV_Nathaniel_Palmer SIMRAD EM120 (12 kHz) LDEO 27/07/2004 01/09/2004 Capetown Auckland

7- GA-2469_ANTAUS_MD120 MARION_DUFRESNE Thompson MarconiTSM 5265(12kHz) IPEV 12/10/2000 07/11/2000 Fremantle La Reunion

8- GA-2493_KNOX03RR RV_Roger_Revelle SIMRAD EM120 (12 kHz) SIO 06/02/2007 21/03/2007 Dunedin Fremantle

- Grid Resolution: 70m

- Number of grids: 13

- Vertical Datum: MSL

- Horizontal Datum: WGS84 UTM45, 46, 47 and 48S

This dataset was compiled and processed by Michele Spinoccia, using CARIS HIPS & SIPS ver 7.1.2.

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, in raw.all format, 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.

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 colored images for presentation and reporting and as final processed data in in ASCII XYZ as well as geotif formats of 70m 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.