AusBathyTopo 30m (Perth) 2026 Grid - A regional-scale depth and elevation dataset and derived terrain variables

Updated: 2026-10-28

The AusBathyTopo 30m (Perth) 2026 Grid comprises a regional-scale bathymetry-topography grid for the Perth region, Western Australia. The grid, or Digital Elevation Model (DEM), is a compilation from individual bathymetry and elevation data sources and covers the area from 109.8° E to 116.2° E and 27.8° S to 34.2° S. This includes the area extending approximately 660 km along the West Australian coast between Kalbarri and Margaret River, up to 530km offshore from Perth, and encompassing the Houtman Abrolhos and Rottnest Islands.  This data package includes the regional grid, a seamless 3D dataset of land and seabed in the Perth region, an accompanying Type Identifier (TID) grid and a suite of datasets for the primary derived terrain variables that support geospatial analysis.  The data package was produced as part of the Resourcing Australia’s Prosperity initiative. The datasets form part of the AusBathyTopo series, providing nationally consistent seabed data to support offshore planning, management and environmental stewardship decisions.The AusBathyTopo 30m (Perth) 2026 grid was compiled using 64 unique data sources from multibeam echosounders, single beam echosounders, LiDAR, 3D seismic first returns and Electronic Navigation Charts (ENC). Australian Hydrographic Office (AHO) supplied ENC tile spot depths provide broad scale bathymetry coverage across the dataset. Airborne LiDAR bathymetry data cover most of the nearshore and coast region, whilst multibeam and single beam data cover shallow and deep-water areas. In areas where no sounding data are available, the bathymetry is provided by an amended surface derived from 2-arc minute ETOPO (Smith and Sandwell, 1997) and 1-arc minute ETOPO (Amante and Eakins, 2008) satellite altimetry data. The Geoscience Australia-developed National Intertidal Digital Elevation Model (NIDEM) (<a href="https://pid.geoscience.gov.au/dataset/ga/72759">http://dx.doi.org/10.26186/5c4fc06a79f76</a>) was used to improve continuity between bathymetry and topography. Terrestrial elevation data was provided by the Shuttle Radar Topography Mission (SRTM) (<a href="https://pid.geoscience.gov.au/dataset/ga/72759">https://pid.geoscience.gov.au/dataset/ga/72759</a>).This new regional-scale bathymetry-topography grid represents decades of data collection, analysis, investment and collaboration from Australia’s seabed mapping community.This dataset is not to be used for navigational purposes. Source Data Types The accompanying Type Identifier (TID) grid identifies the source data type contributing to each cell within the AusBathyTopo 30m (Perth) 2026 grid. Each cell is assigned a TID-code corresponding to the sensor type used to derive the elevation value. Where overlapping data from multiple sensor types exists, the highest quality source was retained. TID codes follow GEBCO standards (https://www.gebco.net/gebco-tid-grid).GEBCO Data Type and Definitions:Land (code 0). Definition: NASBES (code 10). Definition: Single beam - depth value collected by single beam echo-sounder.MBES (code 11). Definition: Multibeam - depth value collected by multibeam echo-sounder.ENC, Elevation (code 14). Definition: ENC sounding - depth value extracted from an Electronic Navigation Chart (ENC).LiDAR (code 15). Definition: LiDAR - depth derived from a bathymetric light detection and ranging sensor.Coast, NIDEM, SDB (code 16). Definition: Depth measured by optical light sensor or satellite-derived bathymetry. Pre-generated grid (code 70). Definition: Pre-generated grid - depth value is taken from a pre-generated grid that is based on mixed source data types, e.g. single beam, multibeam, interpolation etc. Bathymetric Derivatives To support geospatial analysis, this data package includes a series of derived datasets:  aspect, contours, hillshade, rugosity, and slope. These datasets are generated from the AusBathyTopo 30m (Perth) 2026 grid using ArcGIS v3.7.0 Spatial Analyst Tools. The tool parameters used to generate the derived datasets were: Aspect: Method – GeodesicContour: Produced at 25 and 100 m intervalsHillshade: Azimuth – 315°; Altitude: – 45°Rugosity:  Z Unit – Meter; Planar Area Type - Arc-Chord Slope: Output measurement – Degrees; Method – Geodesic; Z unit – Meter