From 1 - 10 / 69
  • In 2008, the performance of 14 statistical and mathematical methods for spatial interpolation was compared using samples of seabed mud content across the Australian Exclusive Economic Zone (AEEZ), which indicated that machine learning methods are generally among the most accurate methods. In this study, we further test the performance of machine learning methods in combination with ordinary kriging (OK) and inverse distance squared (IDS). We aim to identify the most accurate methods for spatial interpolation of seabed mud content in three regions (i.e., N, NE and SW) in AEEZ using samples extracted from Geoscience Australia's Marine Samples Database (MARS). The performance of 18 methods (machine learning methods and their combinations with OK or IDS) is compared using a simulation experiment. The prediction accuracy changes with the methods, inclusion and exclusion of slope, search window size, model averaging and the study region. The combination of RF and OK (RFOK) and the combination of RF and IDS (RFIDS) are, on average, more accurate than the other methods based on the prediction accuracy and visual examination of prediction maps in all three regions when slope is included and when their searching widow size is 12 and 7, respectively. Averaging the predictions of these two most accurate methods could be an alternative for spatial interpolation. The methods identified in this study reduce the prediction error by up to 19% and their predictions depict the transitional zones between geomorphic features in comparison with the control. This study confirmed the effectiveness of combining machine learning methods with OK or IDS and produced an alternative source of methods for spatial interpolation. Procedures employed in this study for selecting the most accurate prediction methods provide guidance for future studies.

  • This is a joint product developed by GA and Skyring Environment Entetrprises. It is an animated CDROM developed specifically in Authoware software for state of the art visual presentation.

  • This dataset contains all multibeam bathymetry data held by Geoscience Australia (GA) dating back to survey obtained since 1993. <b>Value: </b>Bathymetry data is used for a wide range of marine applications including: navigation, environmental assessment, jurisdictional boundaries, resource exploration. <b>Scope: </b>Data holdings lying within the offshore area of Australia, including international waters. <b> To access the AusSeaBed Marine Data Portal </b> use the following link: <a href="https://portal.ga.gov.au/persona/marine#/">https://portal.ga.gov.au/persona/marine#/</a>

  • This dataset provides the spatially continuous data of seabed mud content (sediment fraction < 63 µm) expressed as a weight percentage ranging from 0 to 100%, presented in 0.01 decimal degree resolution raster format. The dataset covers the Australian continental EEZ, including seabed surrounding Tasmania. It does not include areas surrounding Macquarie Island, and the Australian Territories of Norfolk Island, Christmas Island, and Cocos (Keeling) Islands or Australia's marine jurisdiction off of the Territory of Heard and McDonald Islands and the Australian Antarctic Territory. This dataset supersedes previous predictions of sediment mud content for the Australian Margin with demonstrated improvements in accuracy. Accuracy of predictions varies based on density of underlying data and level of seabed complexity. Artefacts occur in this dataset as a result of insufficient samples in relevant regions. This dataset is intended for use at national and regional scales. The dataset may not be appropriate for use at local scales in areas where sample density is insufficient to detect local variation in sediment properties. To obtain the most accurate interpretation of sediment distribution in these areas, it is recommended that additional samples be collected and interpolations updated.

  • A growing need to manage marine biodiversity sustainably at local, regional and global scales cannot be met by applying the limited existing biological data. Abiotic surrogates of biodiversity are thus increasingly valuable in filling the gaps in our knowledge of biodiversity patterns, especially identification of hotspots, habitats needed by endangered or commercially valuable species and systems or processes important to the sustained provision of ecosystem services. This review examines the use of abiotic variables as surrogates for patterns in benthic assemblages with particular regard to how variables are tied to processes affecting biodiversity and how easily those variables can be measured at scales relevant to resource management decisions.

  • The collection consists of field, processed and navigation seismic data plus acquisition processing and interpretation reports. The collection is derived from the marine seismic field programs undertaken by Geoscience Australia, Australian Geological Survey Organisation (AGSO) and Bureau of Mineral Resources (BMR) since the 1980s. Data used by petroleum industry for exploration, GA for frontier petroleum programs and academia for research. 80% of data requests from industry.

  • Simple, conceptual geomorphic models can assist environmental managers in making informed decisions regarding management of the coast at continental and regional scales. This basic information, detected from aerial photographs and/or satellite images, can be used to ascertain the relative significance of several common environmental issues, including: sediment trapping efficiency, turbidity, water circulation, and habitat change due to sedimentation for different types of clastic coastal depositional environments.

  • Diagram produced for the Bureau of Meteorology, in October 2007, showing the area of the eastern Indian Ocean between northwestern Australia and Indonesia with Exclusive Economic Zones of Australia as they would be modified by the Perth Treaty and the 200 nautical mile line from Indonesia. Modified in February 2008 to include Australia's Continental Shelf Claim and a proposed BOM Tsunameter position. Not for sale or distribution For internal use of BOM - Confidential.

  • Geoscience Australia and the National Oceans Office carried out a joint project to produce a consistent, high-quality 9 arc second (0.0025° or ~250m at the equator) bathymetric data grid of those parts of the Australian water column jurisdiction lying between 92º E and 172º E and 8 º S and 60º S. As well as the waters adjacent the continent of Australia and Tasmania, the area selected also covers the area of water column jurisdiction surrounding Macquarie Island, and the Australian Territories of Norfolk Island, Christmas Island, and Cocos (Keeling) Islands. The area selected does not include Australia's marine jurisdiction off the Territory of Heard and McDonald Islands and the Australian Antarctic Territory.

  • The collection consists of seabed samples collected by Geoscience Australia and other organizations since the 1950s. Samples consist of various shallow cores types, rocks derived from dredging, and sea bed sediments collected by grab and dredge methods. A large proportion of samples are refrigerated.