f6618a62-9fda-417b-beb9-7acf5a546dc7 dataset Geoscience Australia (GA) Marine Data Manager +61 2 6249 9277 +61 2 6249 9920 GPO Box 378 Canberra ACT 2601 Australia marine@ga.gov.au http://www.ga.gov.au 2021-10-18T12:22:15 ISO 19139 Geographic Information - Metadata - Implementation Specification 2007 2 9967 4 13693 4 true false 494292.000000 6472640.000000 494292.000000 6527412.000000 534160.000000 6527412.000000 534160.000000 6472640.000000 514226.000000 6500026.000000 center UTM55S EPSG 2.1(3.0.1) Bathymetry Lord Howe 4m GRID lh_4m 2010-10-20 2010-12-20 Geoscience Australia (GA) Marine Data Manager +61 2 6249 9277 +61 2 6249 9920 GPO Box 378 Canberra ACT 2601 Australia marine@ga.gov.au http://www.ga.gov.au Australian Government Department of the Environment and Heritage Metadata Publisher (02) 6274 1111 (02) 6274 1333 GPO Box 787 CANBERRA ACT 2601 metadata@deh.gov.au http://www.deh.gov.au Geoscience Australia carried out a marine survey on Lord Howe Island shelf (NSW) in 2008 (SS062008) to map seabed bathymetry and characterise benthic environments through colocated sampling of surface sediments and infauna, rock coring, observation of benthic habitats using underwater towed video, and measurement of ocean tides and wavegenerated currents. Subbottom profile data was also collected to map sediment thickness and shelf stratigraphy. Data and samples were acquired using the National Facility Research Vessel Southern Surveyor. Bathymetric data from this survey was merged with other preexisting bathymetric data (including LADS) to generate a grid covering 1034 sq km. As part of a separate Geoscience Australia survey in 2007 (TAN0713), an oceanographic mooring was deployed on the northern edge of Lord Howe Island shelf. The mooring was recovered during the 2008 survey following a 6 month deployment. lh_4m is an ArcInfo grid of the Lord Howe survey area produced from the processed EM300 bathymetry data of the survey area using the CARIS HIPS and SIPS software. Geoscience Australia (GA) Marine Data Manager +61 2 6249 9277 +61 2 6249 9920 GPO Box 378 Canberra ACT 2601 Australia marine@ga.gov.au http://www.ga.gov.au ArcINFO grid 1 MARINE Mapping MARINE Geology and Geophysics Downloadable Data subject to agreement This material is released under the Creative Commons Attribution 3.0 Australia Licence. 4 geoscientificInformation Version 6.2 (Build 9200) ; Esri ArcGIS 10.6.1.9270 true 158.939646 159.361188 -31.882032 -31.387358 lh_4m 150 8.85 Unified Code of Units of Measure 32 SDE Raster Dataset Australian Government Department of the Environment and Heritage (02) 6274 1111 (02) 6274 1333 GPO Box 787 CANBERRA ACT 2601 metadata@deh.gov.au ArcInfo grid 1 ERIN Check The positional accuracy is high as required by the multibeam sonar system to properly function true Due to the good quality data being acquired, post processing of the raw data was kept to a minimum. Swath data was processed through Caris HIPS/SIPS version 7.2. First a vessel configuration file was created that the coordinates of the motion sensor and DGPS antenna and patch test offsets were recorded. A new project was then created and the vessel configuration file was attached to the project file. 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. The motion sensor, DGPS and heading data were then cleaned using a filter that averaged adjacent data to remove artifacts. 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. Then a new blank field area was defined that specified the geographic area of study and the coordinate system used. The coordinates for all the study areas were WGS84. 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. In addition, WXTide32 software (http://www.wxtide32.com) with reference to the mean sea level and UTC time was used to obtain tidal information, which in turn was used to correct for the tidal variations in the processing. 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. The processed data was finally exported as XYZ grid soundings and converted into ArcINFO grid. Geophysical Analysis and Data Access project, ISS group, PMD 2000-01-01