Creating Australian Bathytopo Models From Collections of Bathymetric Surveys

Encompassed by sparkling waters and buzzing reefs, Australia’s 34,000 km of coastline are the start of valuable bathymetric resources. A team of scientists at James Cook University in Queensland, Australia, are working in conjunction with AusSeabed and the Australian Hydrographic Office to combine bathymetric surveys into seamless bathytopographic models. Learn how Global Mapper®  and Geographic Calculator® help Robin Beaman and his team piece these models together.

Exclusive Economic Zone

The exclusive economic zone (EEZ) was enacted in 1982 by the United Nations to determine governance over use and exploration of marine resources. The EEZ extends 200 nautical miles (230 miles or 370 km) from a nation’s coast. Australia has the 3rd largest EEZ with 3,283,933 sq mi, following the United States (4,383,000 sq mi) and France (4,514,000 sq mi), which accounts for 8% of the world’s EEZ. This zone gives a country jurisdiction over living and non-living resources such as installing alternative energy, offshore structures, marine research, and setting fish catch restrictions. 

What are Bathytopo Models

Bathymetry is the measurement of water depth, and is used to create maps of the seabed terrain. Topographic maps focus above sea level while bathymetric maps focus on the ocean floor below. Bathytopo models offer a holistic view, including the land along the shore with the seafloor. This shows a more complete 3D view of the terrain and adjacent seafloor that Australia’s coast has to offer.

The Role of AusSeabed

Understanding the topography and structure of the EEZ is crucial for governance. AusSeabed is a national seabed mapping coordination program led by Geoscience Australia. They aim to improve the accessibility of seabed maps. They also coordinate bathymetric data collection efforts to survey gaps throughout the marine region. The bathymetric surveys are freely available in their Marine Data Portal. In addition, collections of these individual surveys are combined into seamless regional- or national-scale models commonly known as the AusBathyTopo series.

AusSeabed works to map the large gaps in knowledge of seabed geomorphology including sediment type and habitats. Currently, about 25% of Australia’s EEZ has been surveyed with high-resolution techniques. This includes multibeam (or swath) echosounders and airborne lasers. In contrast to the more common single beam echosounders or satellite data, these high resolution methods collect swathes of data at different depths. The high resolution seabed mapping provides a more accurate model for further development and protection of resources.

The general principle of the Australian Seabed community is ‘collect once, use many times’. Data collection and bathymetric models are used collaboratively to help parties that utilize the EEZ including government agencies, universities, defense and commercial operators. 

Why Make Bathytopo Models?

Like most projects, it is important to understand why this is being done; why make bathymetric models. Creating seamless 3D models of the land and seabed aims to provide the best representation of the Earth’s surface. From a spatial planning perspective, these 3D models can help with marine windfarm placement or other infrastructure. Conservationists can use these models to identify key ecological features, monitor at risk species, and manage ecosystems. Modeling the seabed shape, or morphology, is also crucial for safety including sea charting, assessing tsunami risks, boundary delineation and marine security. 

In addition to the spatial planning and marine governance that 3D bathymetric models are used for, many of the university scientists use the models for their own research papers. Explore the gallery below to see how researchers have utilized these bathytopo models to visualize their research. 

Creating Bathytopo Models 

While seabed mapping can be done with various kinds of equipment such as autonomous underwater vehicles (AUVs), ships, and satellites, the type of data collected also varies. In order to create bathytopo models, the range of surveys needs to be seamlessly combined. A team of mapping scientists at James Cook University is focused on creating consistent and noise-free models from the collection of multibeam, singlebeam, lidar, and satellite surveys. 

This team is led by Dr. Robin Beaman, a marine geologist and ocean mapping scientist with over 30 years of field experience. He has over 70 publications about his research and expeditions including discovering new species of black coral and understanding submarine landslides with a focus on the Great Barrier Reef and Coral Sea. Beaman and the AusSeabed team “aim … to roll out more of these regional scale, high resolution grids around Australia” in addition to updating existing AusBathyTopo grids. 

Combining hundreds of surveys is not a simple ‘cut and paste’. The source data comes from various locations across 1000s of km, many in different datums and coordinate systems. Beaman’s team works to identify how each data source is georeferenced and then works to align them. This preconditioned data is processed into a 3D digital bathymetric model.  

Global Mapper® to the Rescue 

While geospatially aligning volumes of data can be daunting, Beaman and his team use various GIS software, including Global Mapper®, to precondition the data. Global Mapper, with its support for almost 400 different file formats, allows the scientists to load data from a wide range of sources. They are able to spatially explore the data in an easy-to-use 2D and 3D viewer. 

GeoCalc® Projection Mode

As mentioned previously, the original data sources are in different projections and must be converted to the same coordinate grid and datum before they can be combined into a model. Blue Marble Geographics has 2 core products: Global Mapper, an all-in-one GIS software, and Geographic Calculator®, a repository for data reprojection and coordinate transformations. Instead of switching back and forth between tools, Beaman and his team use the GeoCalc Projection model within Global Mapper to perform projection transformations and align both vertical and horizontal datums. Geographic Calculator simplifies the team’s workflow further with batch processing. When a group of data sets need the same transformation, users are able to batch convert them to consistent horizontal datums before it is input into the bathymetric surface processing step. 

Finishing Touches

Once Beaman and his team have created the large bathytopo models in alternate software, the primary output is a raster grid file format. The AusSeabed Marine Data Portal needs the model to be in point geotiff. This allows users to download areas of interest (or ‘clip/zip/ship’) from the model hosted within the portal. The finished raster grid models are then loaded into Global Mapper and exported as the required 32-bit floating point geotiff files.

With a current Geographic Calculator and Global Mapper license, users like Beaman’s team can utilize the comprehensive geodetic library of Calculator. This includes support for dozens of geoids, ellipsoids and local offset models, along with customer coordinate system support and sharing. See how Global Mapper and Geographic Calculator can simplify your workflow today, try both softwares free for 14 days.

WORK MADE EASY WITH GLOBAL MAPPER

Want to try Global Mapper? Sign up for a 14-day free trial. You can also request a demo from one of our experts to see this workflow or other Global Mapper processing abilities.

Learn More

References:

Ángel Puga-Bernabéu, et al. “Filling the Gap: A 60 Ky Record of Mixed Carbonate-Siliciclastic Turbidite Deposition from the Great Barrier Reef.” Marine and Petroleum Geology, vol. 50, no. 50, 1 Feb. 2014, pp. 40–50, https://doi.org/10.1016/j.marpetgeo.2013.11.009. Accessed 24 Apr. 2025.

AusSeabed-logo. (n.d.). AusSeabed.gov. Retrieved May 15, 2025, from https://www.ausseabed.gov.au/__data/assets/image/0015/60522/AusSeabed-logo_inline.png.

Australia, Australia Government Geoscience. “Seabed Mapping.” www.ausseabed.gov.au, 4 Oct. 2018, www.ausseabed.gov.au/about/mapping. Accessed 22 Apr. 2025.

Cook, James. “Rob Beaman.” Jcu.edu.au, 2024, portfolio.jcu.edu.au/researchers/robin.beaman/. Accessed 24 Apr. 2025.

Flanders Marine Institute (2023). Maritime Boundaries Geodatabase: Maritime Boundaries and Exclusive Economic Zones (200NM), version 12. Available online at https://www.marineregions.org/. https://doi.org/10.14284/632

Horowitz, Jeremy, et al. “Five New Species of Black Coral (Anthozoa; Antipatharia) from the Great Barrier Reef and Coral Sea, Australia.” Zootaxa, vol. 5213, no. 1, 23 Nov. 2022, pp. 1–35, https://doi.org/10.11646/zootaxa.5213.1.1. Accessed 24 Apr. 2025.

Migiro, Geoffrey. “Countries with the Largest Exclusive Economic Zones.” WorldAtlas, 29 June 2018, www.worldatlas.com/articles/countries-with-the-largest-exclusive-economic-zones.html. Accessed 24 Apr. 2025.

NOAA. “What Is the “EEZ”?: Exploration Facts: NOAA Office of Ocean Exploration and Research.” Oceanexplorer.noaa.gov, 2024, oceanexplorer.noaa.gov/facts/useez.html. Accessed 23 Apr. 2025.

Puga-Bernabéu, Ángel, et al. “Submarine Landslides along the Mixed Siliciclastic-Carbonate Margin of the Great Barrier Reef (Offshore Australia).” Geomorphology, vol. 403, 15 Apr. 2022, p. 108179, www.sciencedirect.com/science/article/pii/S0169555X22000721, https://doi.org/10.1016/j.geomorph.2022.108179. Accessed 24 Apr. 2025.

“Robin Beaman - Schmidt Ocean Institute.” Schmidt Ocean Institute, 2021, schmidtocean.org/person/robin-beaman-3/. Accessed 24 Apr. 2025.

Rutledge, Kim, et al. “Bathymetry.” National Geographic Education, National Geographic Society, 24 Sept. 2024, education.nationalgeographic.org/resource/bathymetry/.

United Nations Convention on the Law of the Sea . 2019, www.un.org/Depts/los/convention_agreements/texts/unclos/part5.htm. Accessed 21 Apr. 2025.

W, et al. “Early Aboriginal Pottery Production and Offshore Island Occupation on Jiigurru (Lizard Island Group), Great Barrier Reef, Australia.” Quaternary Science Reviews, vol. 333, 1 Apr. 2024, pp. 108624–108624, https://doi.org/10.1016/j.quascirev.2024.108624.

“What Is the Difference between a Topographic and a Bathymetric Map? : Ocean Exploration Facts: NOAA Office of Ocean Exploration and Research.” NOAA Ocean Exploration, 2012, oceanexplorer.noaa.gov/facts/maps.html. Accessed 24 Apr. 2025.