| USEFUL LINKS dbSEABED - Home - Bibliography - Methods - FAQ - CoreNavigator usSEABED - Home - Atlantic Margin - Gulf of Mexico - Pacific Margin Partners - GSMFC - INSTAAR - PIES - USGS CMG - IOW - USIMS - NOAA NGDC |
Back to dbSEABED
INTRODUCTION The original development of dbSEABED dealt with the Australian Maritime Region - in all, an area comprising 1/12 of the earth's globe. Because of Australia's relatively small population base and inadequate funding for at-sea science, maximum use of existing data had to be made to achieve a workable mapping. This motivated research into the use of datasets that were diverse in their methods, navigation, technologies, aims, standards, formats - and whether numeric or linguistic. The research resulted in a data mining system designed especially for the seabed. These web pages describe the digital GIS coverages that are now available for the seabed materials of the Australian maritime areas. SPATIAL DATA DISTRIBUTION At last count over 275,000 attributed sample sites comprised auSEABED. The distribution - geographic and by attribute - is not uniform, and it is clear from statistics where effort has been concentrated to now, and where major requirements are. Inshore (coastal) zone mapping is the most glaring shortcoming: it is tedious for reasons of the fractal complexity of coastlines, navigation hazards and the need for small-boat operations. Geographically, the most under-mapped regions of shallow depth are the Great Australian Bight, Gulf of Carpentaria and within the complex Great Barrier Reef.
A major feature of compiling auSEABED has been the generosity of many people and institutions in contributing data. The full list is provided at Data Contributors. I thank these people and institutions for their far-sighted attitudes and cooperative spirit. These same people have also provided valuable technical advice on data handling requirements and suitable forms of output. The mean distances between sample sites is quite variable by region and attribute - as shown below. The average closest approach of sites with basic grainsize / carbonate information within the water depth bracket 5- 100m is about ##(TBA) km. A key feature of auSEABED is that as more datasets are added over the years, coverage and resolution steadily increase. Current rates of newly added data are ~300 sites / month, with priority to the inshore zones. The data come from many sources: research (geoscience, oceanography and biology), defence, fisheries and habitat protection, contaminant monitoring, subsea pipeline / cable / anchoring projects, offshore minerals / oil-gas exploration, and testing new technologies. dbSEABED does not ingest geophysical data - namely acoustic echo classification - because one important application is as an independent groundtruthing (validation) for geophysical results, including satellite imagery. OUTPUTS
The primary data delivery from auSEABED is via griddings, which have been compiled at a variety of resolutions and with various selections of data. We generate the grids in ArcView / Spatial Analyst using a straightforward Nearest Neighbour method so that areas far from sites with data are left ungridded (ie. unmapped till expeditions go there). Gridcell sizes and search radii are adjustable per project, but initially we supply generalized grids at 0.1 degr (~10km) resolution on 0.2 degr search radius. Most grids are generated as the mean of values within the search area. ARCview (Spatial Analyst) legends accompany the grids. Catalog of griddings Point
data Visualizations By way of demonstration, several examples are shown below. Generally generation of the visualization is left to clients of auSEABED, for example in the making of multitheme GIS compilations between benthic biological communities and substrate type. However, auSEABED project explores visualization methods and can advise on methods that have proven successful.
Input
To Models
REFERENCES (Printed) Ferns, L. 1999. Environmental inventory of Victoria's marine ecosystems : Stage 4 (Vol. 1) : Final report. Dept. of Natural Resources and Environment, August 1999 Harris, P.T., Porter-Smith, R. Anderson, O., Coleman, R., and Greenslade, D. (2000) GEOMAT - Modelling of Continental Shelf Sediment Mobility in Support of Australia's Regional Marine Planning Process, AGSO Record No. 2000/41, 64 pp. Hohnen, J.G. 2000. Propagation of Southern Right Whale Song in the Great Australian Bight. [B.Sc. Hons. Thesis]. School of Geosciences, The University of Sydney, 89p. Jenkins, C.J. 1997. Building a national scale offshore soils database from both word-based and numeric datasets. Sea Technology, Dec 1997. Jenkins, C.J. & Rawson, G.A. 1994. A GIS of the Australian Seabed. GIS User, 9, 33-35. Jenkins, C.J. 1995. Applications of the AUSEABED Marine GIS/Database in Engineering and Naval Acoustics. Second National Forum on GIS in the Geosciences, Aust. Geol. Surv. Orgnzn, Mar 1995. Ward T.J., R.A. Kenchington, D. Faith and C.R. Margules 1998 Marine BioRap Guidelines: Rapid Assessment of Marine Biological Diversity. CSIRO Australia, Perth. 52 pp. (Electronic) Acknowledgements I thank colleagues at Sydney University (Andrew Rawson, James
Hohnen,
Tanya Schindler, Andy Short), |
