Depth contours at multiple intervals of the Australian 250m 2024 bathymetry grid (AusBathyTopo)

Brief description

This dataset comprises derived bathymetric isobaths (depth contour lines) generated from the Geoscience Australia (GA) AusBathyTopo 250m 2024 gridded bathymetric dataset (https://dx.doi.org/10.26186/150050). The AusBathyTopo 250m grid provides a high-resolution terrain model for Australia, covering ocean and land areas from 92°E to 172°E and 8°S to 60°S at a resolution of 250 metres. The bathymetric contours are clipped to the boundaries of the Australian Exclusive Economic Zone (EEZ: https://amsis-geoscience-au.hub.arcgis.com/datasets/geoscience-au::exclusive-economic-zone-limits/about), and includes all regions including and below Mean Sea Level (MSL). Four contour datasets are provided: 1) 100 m intervals: full EEZ coverage. 2) 5 m intervals: shallow regions between 0–200 m depth (nominally the Australian continental shelf and shallow oceanic features). 3) 1 m intervals: shallow regions between 0–200 m depth. 4) Composite product: Multi-resolution contours with full EEZ coverage, including: • 2 m intervals for depths 0–30 m. • 5 m intervals for depths 30–100 m. • 10 m intervals for depths 100–200 m. • 50 m intervals for depths 200–2,000 m. • 100 m intervals for depths 2,000–8,000 m. These contour datasets are intended for use in marine spatial planning, mapping visualisation, and broad-scale analysis. Due to the smoothing procedures applied during their creation the are not suitable for engineering or high-precision applications. The contours presented through the Web Mapping Services (WMS) linked to this record are optimised for visualisation purposes and have been simplified using a tolerance of 10 meters for efficient rendering in mapping applications. For users requiring full-resolution data, the download packages include the original, unsimplified contour products.

Lineage

Maintenance and Update Frequency: notPlanned

Statement: The Australian Bathymetry Grid 250 m 2024 (AusBathyTopo: https://dx.doi.org/10.26186/150050) was used to generate bathymetric contours.. Data was first smoothed using a Focal Mean algorithm (ArcGIS Pro: Focal Statistics) using a 3 x 3 cell window to reduce high-frequency noise in the DEM. Isobaths were generated (ArcGIS Pro: Contour) at intervals of 1 m, 5 m, and 10 m for depths 0–200 m, 50 m intervals for depths 200–2,000 m, and 100 m intervals for depths 200–8,000 m. Contours were then smoothed using the PAEK algorithm (ArcGIS Pro: Smooth Line) with a 200 m smoothing tolerance to improve visual quality analytical utility. Contours have not been clipped to the boundaries of Lowest Astronomical Tide (LAT), and overlaps with land are present due to the 250 m resolution of the underlying DEM. To mask contours to LAT, see https://doi.org/10.25959/TW80-MD66 for access to LAT shapefiles. These contours are intended for marine use only and are not suitable for land-based applications due to inherent inaccuracies near the land-sea boundary.

Notes

Credit
Acknowledgements of contributors of foundational data to the AusBathyTopo grid: • CSIRO Marine National Facility (https://ror.org/01mae9353) • Australian Hydrographic Office • Geoscience Australia