Reports

Development of the ceq30 bathymetry grid for the Intertidal and Subtidal Habitat Mapping and Conservation Values Assessment for Central Queensland State Waters Project

Authors: Beaman, R.J.

Year: 2019

Publication: Department of Environment and Science, 2019. Development of the ceq30 bathymetry grid for the Intertidal and Subtidal Habitat Mapping and Conservation Values Assessment for Central Queensland State Waters Project, Queensland Government, Brisbane, Australia, pp. 45.

Abstract

The ceq30 bathymetry grid was developed for the Intertidal and Subtidal Habitat Mapping and Conservation Values Assessment for Central Queensland State Waters Project. High-resolution bathymetry data are fundamental to underpin marine habitat mapping and are an essential attribute for use in the ‘Interim Queensland intertidal and subtidal ecosystem classification scheme’.

The ceq30 grid is a compilation of new and existing source bathymetry data, including multibeam and singlebeam echosounder data, Electronic Navigational Chart (ENC) spot depths, airborne lidar bathymetry (ALB) data, Intertidal Extents Model (ITEM v1.0) Digital Elevation Model (DEM) data, satellite derived bathymetry (SDB) and coastline data. Source data are current to 22 June 2017. Shuttle Radar Topographic Mission (SRTM) Digital Surface Model (DSM) data were used as land elevation source data.

The source bathymetry data Total Vertical Uncertainty (TVU) is a measure of maximum allowable vertical uncertainty at the 95% confidence level. The TVU for the source bathymetry data varies from International Hydrographic Organisation (IHO) S44 Order 1a to 2. Alternatively, uncertainty calculations are provided where the TVU for source data falls outside of the standard IHO S44 categories.

All source bathymetry data were subjected to extensive pre-processing as 3D point clouds in order to remove any noise and data spikes. All source data were adjusted to a consistent WGS84 horizontal datum, and wherever possible, to approximate the mean sea level (MSL) vertical datum prior to the grid interpolation process.

The new ceq30 bathymetry grid has a grid pixel resolution of 0.0003° (~30 m), and spans an area latitude 23° to 26° South, longitude 150° to 154° East. The grid has a version date of 12 June 2017. The new grid uses a horizontal datum of WGS84 and a vertical datum approximating MSL. An accompanying TVU grid at the same 0.0003° grid pixel resolution provides the maximum allowable vertical uncertainty at the 95% confidence level, based upon the processed TVU of the underlying source data.

The additional source data and extensive pre-processing effort to remove data spikes and noise have significantly improved the level of detail of seabed geomorphic features seen in the new grid. The bathymetry grid data are recommended for use as a base for mapping or modelling other biophysical attributes for the ‘Interim Queensland intertidal and subtidal ecosystem classification scheme’, such as morphology, sediment grain size and wave energy.

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Link to report on Queensland WetlandInfo site