Project 3DGBR: gbr100 High-resolution Bathymetry for the Great Barrier Reef and Coral Sea (JCU)

Brief description

The gbr100 dataset is a high-resolution bathymetry and Digital Elevation Model (DEM) covering the Great Barrier Reef, Coral Sea and neighbouring Queensland coastline. This DEM has a grid pixel size of 0.001-arc degrees (~100m) with a horizontal datum of WGS84 and a vertical datum of Mean Sea Level (MSL). For the latest version of this dataset download the data from http://deepreef.org/bathymetry/65-3dgbr-bathy.html This dataset was developed as part of the 3DGBR project. This grid utilises the latest available multibeam, singlebeam, lidar and satellite bathymetry source datasets provided by Federal and State Government agencies, in addition to significant new multibeam data collected during research expeditions in the area. The large increase in source bathymetry data added much detail to improving the resolution of the current Australian Bathymetry and Topography Grid (Whiteway, 2009). The gbr100 grid provides new insights into the detailed geomorphic shape and spatial relationships between adjacent seabed features. The accompanying report contains an explanation of the various source datasets used in the development of the new grid, and how the data were treated in order to convert to a similar file format with common horizontal (WGS84) and vertical (mean sea level) datums. Descriptive statistics are presented to show the relative proportion of source data used in the new grid. The report continues with a detailed explanation of the pre-processing and gridding process methodology used to develop the grid. A description is also provided for additional spatial analysis on the new grid in order to derive associated grids and layers. The results section provides a short overview of the improvement of the new grid over the current Australian Bathymetry and Topography Grid (Whiteway, 2009). The report then presents the results of the new grid, called gbr100, and the associated derived map outputs as a series of figures. A table of metadata for the current source data accompanies this report as Appendix 1. The report is available at: http://www.deepreef.org/publications/reports/67-3dgbr-final.html Data details and format: gbr100 bathymetry grid: Height/Depth in metres (MSL) Formats: 19000x18000 pixel grid (32 bit float) in ESRI raster grid file, GMT/netCDF grid file, Fledermaus sd file, 100m contour ESRI shapefile, GeoTiff grid file. Total Vertical Uncertainty: Total Vertical Uncertainty (TVU) in the bathymetry estimated from uncertainty classification of each source dataset. Formats: 19000x18000 pixel grid (32 bit float) in ESRI raster, GeoTiff. Hillshading: Hillshading for full gbr100 and also ocean areas only. Derived from the gbr100 grid. Format: 19000x18000 pixel grid (8 bit) in GeoTiff. Funding history: This dataset was initially developed as part of project 2.5i.1 from the MTSRF program (2010). Subsequent versions of the dataset were developed from other funding sources. Version history: - July 2010 - Version 1 - Dec 2014 - Version 3 This version incorporates dozens of new bathymetric surveys including many new navy LADS surveys and some satellite derived bathy to fill in some gaps left by LADS. - Jan 2016 - Version 4 This version incorporates estimates of bathymetry from satellite imagery in shallow clear waters. Data Location: This dataset is filed in the eAtlas enduring data repository at: data\ongoing\GBR_JCU_Beaman_3DGBR-bathymetry-gbr100 eAtlas Processing: To visualize this dataset on the eAtlas the format of the data was converted from the ESRI ArcInfo grid format into a GeoTiff format. This was done by loading the data in ArcMap then exporting it as a GeoTiff image. Overview images and final compression options were then performed using GDAL tools.

Notes

A high-resolution DEM is a critical 3D dataset required to accurately simulate water mixing and current flow within a whole-of-GBR scale hydrodynamic model. In addition, a new grid is required to improve the geomorphic detail about the location and spatial extent of seabed features for much of the GBR shelf and Coral Sea region. The new grid utilised the latest data sourced from ship-based multibeam and singlebeam echosounder surveys, airborne LiDAR bathymetry surveys, and satellite data. A full description of the project is available at: http://www.deepreef.org/projects/48-depth-model-gbr.html

Lineage

The gbr100 DEM was compiled from a number of source datasets including the Australian Bathymetry and Topography Grid (Geoscience Australia, 2009), multibeam data (Geoscience Australia, Australian Hydrographic Service), singlebeam (Geoscience Australia), lidar (Royal AUstralian Navy), coastline data (Geoscience Australia), satellite elevation data from the Shuttle Radar Topographic Mission (NASA). See the final report for full details. AUSTRALIAN HYDROGRAPHIC SERVICE NOTICE: Not to be used for navigation. Certain material in this product are reproduced under licence by permission of The Australian Hydrographic Service © Commonwealth of Australia 2010. All rights reserved. This information may not be copied, reproduced, translated, or reduced to any electronic medium or machine readable form, in whole or part, without the prior written consent of the Australian Hydrographic Service. GEOSCIENCE AUSTRALIA NOTICE: This gbr100 DEM incorporates data which are © Commonwealth of Australia (Geoscience Australia) 2010. The Commonwealth gives no warranty regarding the data's accuracy, completeness, currency or suitability for any particular purpose. This dataset has been compiled from a wide range of data sources of varying resolution and accuracy. The resulting gbr100 DEM has some reefs shifted by up to 500m in the Swain Reefs area, due to a lack of source bathymetry data.