This metadata record is a modified child record of an original parent record originating from custodians of data associated with Geoscience Australia (The identifier of the parent record is ANZCW0703006701, and can be found on the Australian Spatial Data Directory website - see the URL given below). A bathymetric grid of the Macquarie Island Region (Longitudes 151 E and 167 E, Latitudes 48 S and 62 S) was produced. In doing so, the individual datasets used were closely examined and any deficiencies noted for further follow up or were rectified immediately and the changes documented. These datasets include modern multibeam data, coastline data obtained from georeferenced SPOT imagery, hydrographic quality data, echosounder data from research and fishing vessels and satellite derived bathymetric data. A hierarchical system was employed whereby the best and most extensive datasets were gridded first and applied as a mask to the next best dataset. A new masking grid would be formed from these datasets to pass non-overlapping data in the next best dataset. This procedure was employed until finally the satellite data were masked. All the various levels of masked data were then brought together by the gridding algorithm (Intrepid and Desmond Fitzgerald Associates) and an ERMapper format grid produced. A grid cell size of 0.00225 (nominal 250m) was used with many iterations of minimum curvature gridding and several passes of smoothing. The final grid is available in geotiff, ArcInfo ascii and xyz text formats. A detailed report of the work completed is also available.

This dataset is a bathymetric grid of the region 60E to 90E and 48.45S to 70S, created in a geographic coordinate system based on a WGS84 horizontal datum. The grid has a cell size of 0.005 degrees. Most of the work involved creating a bathymetric grid of the region 60E to 90E and 55S to 70S which was generated from the latest available multibeam swath bathymetry, fisheries' surveys and satellite altimetry data. A report outlining the development of this grid is available for download (see the related url below). This grid was then merged with the bathymetric grid described by the metadata record 'Bathymetric Grid of Heard Island - Kerguelen Plateau Region (2005)', which covers the region 68E to 80E and 48S to 56S. Hence the final grid has two 'No data' areas between 48.45S to 55S: 60E to 68E and 80E to 90E. The final grid is available for download as a geotiff and ArcInfo ascii file and contours derived from the grid are available for download as a shapefile (see the related urls below).

A high resolution bathymetric grid of the nearshore area at Casey station, Antarctica was produced by Geoscience Australia by combining data from two multibeam hydrographic surveys: 1) A survey conducted by the Royal Australian Navy in 2013/14. Refer to the metadata record 'Hydrographic survey HI545 by the RAN Australian Hydrographic Service at Casey, December 2013 to January 2014' with ID HI545_hydrographic_survey. 2) A survey conducted by Geoscience Australia and the Royal Australian Navy in 2014/15. Refer to the metadata record 'Hydrographic survey HI560 by the RAN Australian Hydrographic Service at Casey, December 2014 to February 2015' with ID HI560_hydrographic_survey and the metadata record 'Seafloor Mapping Survey, Windmill Islands and Casey region, Antarctica, December 2014 - February 2015' with ID AAS_3326_seafloor_mapping_casey_2014_15. The grid has a cell size of one metre and is stored in a UTM Zone 49S projection, based on WGS84. Further information is available from the Geoscience Australia website (see a Related URL).

This GIS dataset is the result of the interpolation of bathymetry from depth measurements made in Long and Tryne Fjords in the Vestfold Hills, Antarctica (see Entry: VH_bathy_99). The Topogrid command within the ArcInfo GIS software, version 8.0.2, was used to do the interpolation. Coastline and spot height (heights above sea level) data, extracted from the Australian Antarctic Data Centre's Vestfold Hills topographic GIS dataset (see Entry: vest_hills_gis), was also used as input data to optimise the interpolation close to the coastline. See related URLs for a map showing the interpolated bathymetry.

From February to March 2010, Geoscience Australia (GA) conducted a multibeam sonar survey of the coastal waters of the Vestfold Hills in the Australian Antarctic Territory. The survey was conducted jointly with Australian Antarctic Division (AAD) and the Deployable Geospatial Survey Team (DGST) of the Royal Australian Navy. The survey was aimed primarily at understanding the character of the sea floor around Davis Station to better inform studies of the benthic biota and the possible impacts of the Davis sewage outfall. DGST were involved to ensure that the bathymetric data could be used to update and extend the nautical charts of the Davis area. The survey was conducted using GA's Kongsberg EM3002D multibeam echo sounder and C-Nav Differential GPS system mounted on the AAD work boat Howard Burton. Sixteen under water videos were also collected using the GA Raytech camera system and 3 grabs were also collected to compliment an intensive sampling program by AAD divers and a sampling program conducted in the 1990's by University of Tasmania (Franklin, 1996). An area of 42 km2 was surveyed intensively immediately off Davis and additional survey lines were run to Long Fjord in the north and to Crooked Fjord and the Sorsdal Glacier in the south. The main survey area had between 150% and 200% coverage as the seabed was esonified from opposing angles to resolve and provide detail to the numerous features of the seafloor such as rocky reefs, iceberg scours, boulders, anchor chain drag marks and grounded icebergs. The new high resolution data provided detailed maps of sea bed morphology and texture classification to complement sample data. Sixteen video transects were collected and 3 grab samples collected in water too deep for the Australian Antarctic Division Diving program. New high resolution bathymetric grids have been prepared for scientific use and further processing for hydrographic charting is ongoing. A new sea floor geomorphic map has been prepared using the multibeam data, preliminary video and sampling data. The project was a component of Australian Antarctic Science (AAS) Project 2201 - Natural Variability and Human Induced Change on Antarctic Nearshore Marine Benthic Communities. In 2011, Dr Phil O'Brien provided to the Australian Antarctic Data Centre the following interim data: 75 cm multibeam data in CARIS format; and a 4 metre resolution bathymetric grid and an image of the sea floor, both derived from the 75 cm multibeam data. This data was made available for download from this metadata record. In August 2013, Geoscience Australia released 2 metre resolution bathymetric and backscatter grids after further processing of the multibeam data. The bathymetry and backscatter data have now been fully processed checked and validated by Geoscience Australia and supersede the interim data. The interim data has been archived by the Australian Antarctic Data Centre. The 2 metre resolution grids and final report are available for download from the Geoscience Australia website.

Gridded bathymetry (40 m cell size) of the slope environment of Swains Island, American Samoa. Almost complete bottom coverage was achieved in depths between 7 and 4800 m. The multibeam data are from the Simrad EM300 system aboard the NOAA Ship Hi'ialakai, and the Reson 8101ER system aboard the R/V AHI and were collected from 10th - 13th February 2006.

Pre-processed satellite imagery [Davis Station_Preprocessed_WV2_Shallow Water.tif] IMPORTANT: This data cannot be shared due to licensing conditions and is provided for archival purposes only. Worldview-2 Imagery was provided at Processing level 2A in UTM 44S projection. The following Pre-processing steps were applied: 1. Radiometric Correction: Digital Numbers converted to TOA Reflectance 2. Atmospheric Correction: Dark Object Subtraction 3. Masking: Masking of Land and Ice features using classification of accompanying PAN imagery 4. Shallow Water Masking: Deep water masked out by thresh-holding the green and yellow bands The pre-processed data is provided as an 8-band Geotiff in UTM 44s with pixels of 2 m. Satellite-derived bathymetry grid [Davis Station_SDB_utm44s_alat.tiff] This bathymetry dataset was produced by applying the SMART-SDB model to Worldview 2 Multispectral Image acquired on 20120118 at 04:52:17Z. Multibeam bathymetry data acquired in February-March 20101 using a Kongsberg EM 3002D MBES, with vertical and horizontal accuracy of 0.38m and 1.95m respectively, was used for both calibration and validation of the SMART-SDB model. Derived data was smoothed using a low pass filter, and manually cleaned for erroneous returns (however some may still exist). A description of the methods is available in the attached reports. Projection: UTM44S Tidal datum: ALAT (approximate lowest astronomical tide) Format: geotiff, ASCI xyz Depths Derived from Satellite Imagery. For SA awareness only. Not for Navigation. Vertical Accuracy is un-assessable and should be considered worse than ZOC C. Undetected features significant to surface navigation may exist. Bathymetry map (Davis Station SDB Chart_OFFICIAL.pdf) This map shows the hydrographic chart from Davis Station overlayed with the new satellite-derived bathymetry data. Python Scripts and Guide These scripts were developed to automate extraction of satellite-derived bathymetry from the Worldview-2 imagery. Details of the scripts and how to apply them are outlined in the guide: Antarctica SDB Project How To.docx Final report [AASP4392_Antarctica SDB Project_FINAL_REPORT.docx] This report outlines the objectives, methods, results and conclusions for the satellite-derived bathymetry project (AASP4392). It has not been peer-reviewed. 1 A collaborative Australian Hydrographic Service, Geoscience Australia and Australian Antarctic Division survey on the Howard Burton acquired multibeam bathymetry data using a Kongsberg EM 3002D MBES with vertical and horizontal accuracy of 0.38m and 1.95m respectively in the nearshore waters of the Vestfold Hills in February-March 2010. This survey is part of Australian Antarctic Project (AAP) 5093: Hydrographic Surveying and Seabed Characterisation (CI: Ursula Harris) The data was extracted from the Australian Hydrographic Office database (20100329 Hydrographic survey) and is available at: O'Brien, P.E. (2011) Coastal seabed mapping survey, Vestfold Hills, Antarctica, February-March 2010, Ver. 2, Australian Antarctic Data Centre https://data.aad.gov.au/metadata/records/Davis_multibeam_grids)

Tides were measured using a portable pressure transducer secured just below low water line. A 22 hour record was obtained. A connection was made to the local Pageos benchmark by leveling and a 2 hour GPS observation. Additionally, the National Tidal Centre also has tidal data from Heard Island for 1948, 1980 and from 1986-1987. Documentation dated 2001-03-07 Heard Island Tide Gauge. A Platypus Engineering tide gauge was deployed in a heavy steel tetrahedral mooring in Atlas Cove in 1993. Two attempts have been made to recover the gauge without success. In March 1997 a temporary tide gauge was used to obtain a 22 hour record. A rock bolt was placed in the rock close to the deployment site and a connection was made to the Pageos Site by a 2 hour GPS observation. A level and staff was used to measure the height of the temporary gauge relative to the BM (AUS258). From these observations an approximate MSL can be found. Some further information about the data can be found in the download file.

Geoscience Australia, the Royal Australian Navy (RAN) and the Australian Antarctic Division (AAD) conducted a hydrographic and seafloor characterisation survey in nearshore waters offshore from Davis Station in the Australian Antarctic Territory. Multibeam bathymetry data was acquired during January-February 2017 and a high-resolution (2 m) bathymetry grid produced for the survey area.

A routine was developed in R ('bathy_plots.R') to plot bathymetry data over time during individual CEAMARC events. This is so we can analyse benthic data in relation to habitat, ie. did we trawl over a slope or was the sea floor relatively flat. Note that the depth range in the plots is autoscaled to the data, so a small range in depths appears as a scatetring of points. As long as you look at the depth scale though interpretation will be ok. The R files need a file of bathymetry data in '200708V3_one_minute.csv' which is a file containing a data export from the underway PostgreSQL ship database and 'events.csv' which is a stripped down version of the events export from the ship board events database export. If you wish to run the code again you may need to change the pathnames in the R script to relevant locations. If you have opened the csv files in excel at any stage and the R script gets an error you may need to format the date/time columns as yyyy-mm-dd hh;mm:ss, save and close the file as csv without opening it again and then run the R script. However, all output files are here for every CEAMARC event. Filenames contain a reference to CEAMARC event id. Files are in eps format and can be viewed using Ghostview which is available as a free download on the internet.