Satellite ASTER Geoscience Map of Australia
The ASTER geoscience map of Australia will be publically released during the 34th International Geological Congress in Brisbane, Australia.
The ASTER geoscience map of Australia is a set of public, web-accessible digital geoscience products generated from satellite ASTER data.
ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is a Japanese imaging instrument on board USA’s TERRA satellite. The multispectral imaging sensor is the world’s first and to date only “geoscience tuned” satellite Earth Observing System.
The Western Australian Centre of Excellence for 3D Mineral Mapping (C3DMM), led by CSIRO, developed new methods and software that transformed the raw ASTER data into a new suite of 17 geoscience products (e.g. Figure 1).
The ASTER geoscience maps of Australia represent the world’s first continentscale maps of the Earth’s surface mineralogy.
ASTER has 14 spectral bands spanning wavelengths sensitive to important rock forming minerals, including: Iron oxides; clays; carbonates; quartz; muscovite and chlorite.
Each ASTER image covers a 60 by 60 km area with individual pixel elements ranging from 15 to 90 m suitable for geoscience mapping from continent (1:2,500,000) down to mineral prospect (1:50,000) scale. The Australian mosaic is sourced from ~35,000 ASTER scenes with approximately 3500 used in the final mosaic.
Figure 1: Satellite ASTER Geoscience map of iron oxide composition.
The image pre-processing methodology to generate the 17 WA ASTER geoscience map products involves correcting for complicating instrument, atmosphere and vegetation effects. The resultant ASTER geoscience maps provide new mineral information not available from other current technologies, valuable for more accurate mapping of the regolith cover that blankets much of Australia. They also help to find those often small islands of exposed bedrock geology that may be overprinted by footprints of mineralised systems (Figure 2).
The final geoscience products represent “mineral group” information only. The reason for this is that the determination of the abundance and chemistry of specific minerals requires even higher resolution systems often termed as hyperspectral, which measures hundreds of spectral bands, such as the Australian airborne HyMap™ system (www.hyvista.com). A suite of hyperspectral satellites will be launched from 2015 (www.isiswg.org) and CSIRO is working with International satellite teams to again capture their benefit for Australia.
CSIRO has been collaborating with Japanese space agencies and NASA for twenty years in order to capture the opportunity of continental-scale mapping of land surface mineralogy over Australia. The presented ASTER Geoscience Maps of Australia were made possible by funding through the WA Exploration Incentive Scheme and WA Centres of Excellence funding (for establishing C3DMM), as well as support by the Australian Federal, State and Territory Geological Surveys.
Accessing the maps
The Australian ASTER geoscience maps are digitally available to the public as GIS-compatible images (e.g. TIF format) or in image-processing software format (e.g. BSQ with headers). The State ASTER maps have been carved into 1:1,000,000 mapsheets with individual file sizes reduced to ~100 Mbytes each.
View the ASTER maps using World Wind http://www.ga.gov.au/aster-viewer
View and download ASTER maps:
• http://geoscience.nt.gov.au/giws or
• CSIRO's C3DMM webpage or
Order the complete Australian ASTER geoscience data set, including the BSQ data (~1.2 Terabytes), from Geoscience Australia Sales Centre (firstname.lastname@example.org).
These Version 1 satellite ASTER geoscience maps of Australia can be improved by removing complicating vegetation and instrument noise effects. Work has also begun preparing for the next generation of higher-resolution, geoscience-tuned satellites, such as Worldview-3 (2014), PRISMA (2014), HISUI (2015) and EnMap (2015).