|
|
|
You are here: Home > GA Metadata
|
||||
|
GA Metadata Related Links |
Geomorphology of the Australian Margin and adjacent seafloor (National Geoscience Dataset)Note: This metadata describes the dataset in accordance with the ANZLIC (Australia New Zealand Land Information Council) Core Metadata Guidelines Version 2. Dataset citationANZLIC unique identifier: ANZCW0703015075 Title: Geomorphology of the Australian Margin and adjacent seafloor (National Geoscience Dataset) CustodianCustodian: Geoscience Australia Jurisdiction: Australia DescriptionAbstract: The geomorphic features of the seafloor in the Australian Marine Jurisdiction were identified using the Australian Bathymetry and Topography dataset (Webster & Petkovic 2005). Twenty one feature types were identified and mapped for an area including the seafloor surrounding the Australian mainland and island territories of Christmas, Cocos (Keeling), Macquarie, and Norfolk Islands (Heap & Harris 2008). Some examples of these geomorphic features include: abyssal plains, trenches, canyons, and seamounts. ANZLIC search words:
Spatial domain:
Geographic extent name: AUSTRALIA EXCLUDING EXTERNAL TERRITORIES - AUS - Australia - Australia Geographic extent polygon: 92 -8, 172 -8, 172 -60, 92 -60, 92 -8, Note: The format for each Geographic extent name is: Name - Identifier - Category - Jurisdiction (as appropriate) See GEN Register
Data currencyBeginning date: 2005-05-31 Ending date: 2005-05-31 Dataset statusProgress: Complete Maintenance and update frequency: Not Known Access
Access constraints: This material is released under the Creative Commons Attribution 3.0 Australia Licence. Free Data DownloadData qualityLineage: Initially, the geomorphic features were captured in 2002 as part of a program run by Geoscience Australia and the National Oceans office to create a spatial inventory of benthic habitats for Australia?s marine jurisdiction. The original bathymetry database contained more than 200 million data points from 931 marine surveys (Petkovic & Buchanan 2002). A further 87.5 million data points were added for a later study by Heap & Harris (2008). These additional data points were extracted from the new bathymetry model of the Australian margin and adjacent seafloor (Webster & Petkovic 2005). The geomorphic features are defined by the International Hydrographic Office (IHO, 2001), with one additional feature identified as type 21 ? Sandwave/Sand bank (Heap & Harris 2008). The geomorphic features were identified using a 250 m spatial resolution bathymetry model with reference to previously published geological studies. In most cases, the feature boundaries corresponded to already published boundaries or were defined based on obvious bathymetric features, supplemented by high-resolution seismic reflection and sedimentary data. Where appropriate, the feature boundaries and classifications are consistent with United Nations Law of the Sea boundaries. The identification of shelf valleys and submarine canyons on the continental slope was aided by the use of predicted drainage maps. All the features were identified on the contour and false colour maps and drawn by hand onto transparent compilation maps. When completed, the compilation maps were scanned, georeferenced and the separate polygons were digitised and stored as an ARC/GIS shape file. Care was taken where separate maps sheets joined to ensure that features were correctly identified and retained their identity across the boundaries. Positional accuracy: Positional accuracy of individual geomorphic features boundaries varies depending on the source data. Due to the scale of the map, and quality of the source, the smallest feature that could be reliably resolved was approximately 10 km in length. Attribute accuracy: No attribute for data quality exists at this stage. This attribute will be updated once a reliability map for the source bathymetric data has been generated. The reliability map will be based on the spatial distribution of soundings. Logical Consistency: All bathymetric datasets once reduced to 9 x 250 m grids for the Australia EEZ were examined visually for data consistency. In some circumstances individual datasets were identified as inconsistent within the grid and either left out of the final grid or were corrected. Terms and nomenclature used to describe geomorphic features of the seabed are based on definitions endorsed by the International Hydrographic Organisation (IHO, 2001), with the addition of one extra feature type; type 21 ? Sandwave/Sand bank. Adopting ISO terms ensures a standard nomenclature that is widely recognised. Regional data sets were then compiled as a single national coverage. Tests were also carried out on the data for completeness, correct spatial representation, attribute accuracy, and logical consistency and correctness. Completeness: Coverage: The geomorphic units cover 100% of the Australia Exclusive Economic Zone. The raw data that makes up the bathymetry grid is derived from numerous sources and has been obtained opportunistically hence the actual data coverage is generally patchy and irregular. A data density map for the bathymetry grids has not yet been produced. Contact information
Metadata informationMetadata date: 2013-03-08 Additional metadataMetadata reference XHTML: http://www.ga.gov.au/meta/ANZCW0703015075.html Metadata reference XML: http://www.ga.gov.au/meta/ANZCW0703015075.xml Heap, A. D. and Harris, P. T. 2008. Geomorphology of the Australian margin and adjacent seafloor. Australian Journal of Earth Sciences, Vol. 55 Issue 4, pp 555-585. Authors:Heap, A.D. Harris, P. |
|||
|
SPATIAL INFORMATION FOR THE NATION
|