May 2006

• Survey detour discovers underwater mountain
• Flood studies to benefit communities
• New Geodata for ACT Region available
• Success with new source of imagery

Survey detour discovers underwater mountain

An underwater mountain rising 300m from the sea floor, and 5km in length has been discovered using a swath mapper onboard the National Facility Research Vessel, the Southern Surveyor. The discovery came about unexpectedly during a voyage to investigate continental shelf processes between Cape Leeuwin and the Great Australian Bight.

The underwater mountain, named Mt Gabi by the Chief Scientist of the expedition, Professor Charitha Pattiaratchi from the University of Western Australia, is located 50kms south of Augusta on the Western Australian coast.

The unexpected find came about in April when Cameron Buchanan, a Multibeam Sonar Specialist from Geoscience Australia, took advantage of a last minute detour to the planned schedule when the vessel had to increase its fresh water supply.

"I was asked to design a 24 hour swath survey as we had to cruise around for a period to generate more fresh water, so the find was fortuitous," said Cameron.

"Some mapping had been conducted in the area by French researchers, but I knew that we were very close to an area where some data had not been collected. So I was able to design a survey that covered the head of the Leeuwin Canyon, an unknown area."

Although Mt Gabi is not an unusual feature on the seabed in this region, exercises like this demonstrate that there are large areas of the sea floor that remain uncharted and scientists like Cameron Buchanan will play a valuable role completing this enormous task.

Geoscience Australia provides technical support to operate the specialised swath mapping equipment onboard the Southern Surveyor.

Flood studies to benefit communities

The first online database of existing flood studies at a national level includes over a thousand sets of information.

Developed by Geoscience Australia, with funding from the Department of Transport and Regional Services, the National Database of Riverine Flood Hazard and Risk Studies allows online searches using comprehensive information of flood studies undertaken between 1980-2004. With the cooperation of many agencies who contributed data, the new resource is the culmination of two years work and will be of benefit to anyone involved in floodplain management.

The database is a result of the acceptance of 12 Reform Commitments into natural disaster mitigation, relief and recovery arrangements in 2003 by the Council of Australian Governments. The Department of Transport and Regional Services engaged Geoscience Australia to act as its technical advisor in a national program of natural hazard risk assessment. Geoscience Australia has developed the database of riverine flood studies as a step in this process.

"At a national and a regional level, the database can be used as a tool to assist in determining the areas of high flood hazard and risk, and to aid comparisons of relative risk between urban centres. It may also be used to identify areas where further research needs to be undertaken, for example, where future studies should have a greater focus on risk assessment," said Miriam Middelmann, a research scientist with Geoscience Australia.

"The database provides the foundation from which to identify and prioritise areas for future flood studies and improves our knowledge of national flood risk. You can see what studies have been undertaken for a particular area, what techniques were used and, where available, what data has been used and who the custodian is. It means that organisations wishing to commission a flood study, particularly small Councils who may not have much experience dealing with flooding or risk assessment, can learn from the work that has been undertaken in other areas," she said.

New Geodata for ACT Region available

Geoscience Australia has released 1:100 000 scale vector data for the ACT Region which enables users with Geographic Information Systems (GIS) to apply the data in specialised applications.

Called GEODATA TOPO 100K ACT Region, it is a vector representation of the major topographical features appearing on the ACT Region 1:100 000 scale topographic map and is primarily designed to provide high quality data for mapping and GIS professionals.

The data is available free on line or as a packaged product on CD for only $99. Both versions are available in Personal Geodatabase, ESRI Shapefiles and MapInfo Mid/Mif formats. ER Mapper ECW Raster format data is also included, adding to its versatility.

Data is presented in the following themes: Administration, Aviation, Cartography, Culture, Drainage, Framework, Habitation, Industry, Physiography, Rail transport, Relief, Road transport, Series Index, Survey Marks, Utility, Vegetation and Water-bodies.

The packaged version can be obtained from the Geoscience Australia Sales Centre on Freecall 1800 800173 (within Australia).

Success with new source of imagery

Geoscience Australia (GA) has successfully received its first image from the China/Brazil Earth Resource Satellite 2 (CBERS). Images from CBERS can provide valuable information to land managers and policy makers about the nature of Australia's land surface, specifically in areas such as environmental monitoring, agriculture, mapping and emergency management.

Launched in October 2003, the China/Brazil satellite can produce images to 20 metre resolution that completely cover Australia every 26 days. Alternatively, images over particular points can be acquired every few days. This repeat coverage helps to build an archive of Australian landscapes for studies that look at the effect of human impact and natural changes over time.

"This successful downlink helps pave the way for further collaboration between GA and the China Center for Resource Satellite Data and Applications (CRESDA). We are now looking at future downlinking of CBERS data as one alternative to meet our operational requirements in light of the now ailing Landsat systems," said Dr Adam Lewis, Manager of GA’s Spatial Information Access & Remote Sensing Group.

GA currently acquires satellite data from a range of satellites through the Australian Centre for Remote Sensing (ACRES) and has been using images from the Landsat series of satellites since 1979.

Landsat data has provided a comprehensive spatial archive to governments and industry, but as the Landsat satellites age, users have become concerned about continuity of reliable and cost effective satellite imagery. Collaboration with CRESDA is a direct response to this concern, with GA looking to a number of international satellite operators to secure access to alternative sources of data.

"This was a key step in our discussions with CRESDA, which could lead to regular access of CRESDA satellites on an operational basis," said Dr Lewis. "We need to ensure that Government agencies, such as the Australian Greenhouse Office, can confidently plan their programs well into the future."