Ratio of U over Th derived from the filtered U and Th grids. The Radiometric Map of Australia dataset comprises grids of potassium (K), uranium (U) and thorium (Th) element concentrations, and derivatives of these grids. This third edition was derived by seamlessly merging 45 new survey grids with the Second Edition Radiometric Map of Australia (Minty et al., 2010). Details of the specifications of individual airborne surveys can be found in the 2014 Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). Matching of the grids in the database was achieved using a program called Gridmerge, originally developed within Geoscience Australia and has now been commercialised. This program was used to merge 45 new surveys to the Second Edition Radiometric Map of Australia. The second edition merged over 550 individual grids to create the compilation (Minty et al., 2009), and the Australia-wide Airborne Geophysical Survey (AWAGS) airborne radiometric data was used to control the base levels of those survey grids which overlapped the AWAGS data (Milligan et al., 2009). As the second edition was used as a base grid for the Gridmerge operation the new Third Edition is essentially levelled to AWAGS. Filtering: Potassium, uranium, thorium and dose rate grids are available in both filtered and unfiltered versions. The low-pass filtering was achieved by applying a 7-point, degree-3 Savitzky-Golay filter (Savitzky and Golay, 1964) to each of the original survey grids prior to grid merging.

Ratio of Th over K derived from the filtered Th and K grids. The Radiometric Map of Australia dataset comprises gridsof potassium (K), uranium (U) and thorium (Th) element concentrations, and derivatives of these grids. This third edition was derived by seamlessly merging 45 new survey grids with the Second Edition Radiometric Map of Australia (Minty et al., 2010). Details of the specifications of individual airborne surveys can be found in the 2014 Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). Matching of the grids in the database was achieved using a program called Gridmerge, originally developed within Geoscience Australia and has now been commercialised. This program was used to merge 45 new surveys to the Second Edition Radiometric Map of Australia. The second edition merged over 550 individual grids to create the compilation (Minty et al., 2009), and the Australia-wide Airborne Geophysical Survey (AWAGS) airborne radiometric data was used to control the base levels of those survey grids which overlapped the AWAGS data (Milligan et al., 2009). As the second edition was used as a base grid for the Gridmerge operation the new Third Edition is essentially levelled to AWAGS. Filtering: Potassium, uranium, thorium and dose rate grids are available in both filtered and unfiltered versions. The low-pass filtering was achieved by applying a 7-point, degree-3 Savitzky-Golay filter (Savitzky and Golay, 1964) to each of the original survey grids prior to grid merging.

Terrestrial dose rate derived as a linear combination of the filtered K, U and Th grids described above (see Minty et al., 2009). Unit of measure = nG/h. The Radiometric Map of Australia dataset comprises gridsof potassium (K), uranium (U) and thorium (Th) element concentrations, and derivatives of these grids. This third edition was derived by seamlessly merging 45 new survey grids with the Second Edition Radiometric Map of Australia (Minty et al., 2010). Details of the specifications of individual airborne surveys can be found in the 2014 Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). Matching of the grids in the database was achieved using a program called Gridmerge, originally developed within Geoscience Australia and has now been commercialised. This program was used to merge 45 new surveys to the Second Edition Radiometric Map of Australia. The second edition merged over 550 individual grids to create the compilation (Minty et al., 2009), and the Australia-wide Airborne Geophysical Survey (AWAGS) airborne radiometric data was used to control the base levels of those survey grids which overlapped the AWAGS data (Milligan et al., 2009). As the second edition was used as a base grid for the Gridmerge operation the new Third Edition is essentially levelled to AWAGS. Filtering: Potassium, uranium, thorium and dose rate grids are available in both filtered and unfiltered versions. The low-pass filtering was achieved by applying a 7-point, degree-3 Savitzky-Golay filter (Savitzky and Golay, 1964) to each of the original survey grids prior to grid merging.

Unfiltered terrestrial dose rate derived as a linear combination of the unfiltered K, U and Th grids (Minty et al., 2009). Unit of measure: nG/h. The Radiometric Map of Australia dataset comprises gridsof potassium (K), uranium (U) and thorium (Th) element concentrations, and derivatives of these grids. This third edition was derived by seamlessly merging 45 new survey grids with the Second Edition Radiometric Map of Australia (Minty et al., 2010). Details of the specifications of individual airborne surveys can be found in the 2014 Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). Matching of the grids in the database was achieved using a program called Gridmerge, originally developed within Geoscience Australia and has now been commercialised. This program was used to merge 45 new surveys to the Second Edition Radiometric Map of Australia. The second edition merged over 550 individual grids to create the compilation (Minty et al., 2009), and the Australia-wide Airborne Geophysical Survey (AWAGS) airborne radiometric data was used to control the base levels of those survey grids which overlapped the AWAGS data (Milligan et al., 2009). As the second edition was used as a base grid for the Gridmerge operation the new Third Edition is essentially levelled to AWAGS. Filtering: Potassium, uranium, thorium and dose rate grids are available in both filtered and unfiltered versions. The low-pass filtering was achieved by applying a 7-point, degree-3 Savitzky-Golay filter (Savitzky and Golay, 1964) to each of the original survey grids prior to grid merging.

Hue-Saturation-Intensity (HSI) colour image of the national Gravity Anomaly grid, 2010. This image is made from a grid that represents gravity anomalies of the Australian region. The grid combines accurate onshore gravity measurements, with satellite data over the offshore region. The cell values represent simple Bouguer anomalies at a density of 2.67 tonnes per cubic metre onshore and free-air anomalies offshore. The grid cell size is 0.5 minutes of arc, which is equivalent to about 800 metres.

The onshore Bouguer gravity grid (2010) represents gravity anomalies of the Australian continent and surrounding region. The cell values represent simple Bouguer anomalies at a density of 2.67 tonnes per cubic metre. The grid cell size is 0.5 minutes of arc, which is equivalent to about 800 metres.

Coastline of Australia, sourced from the 1:1M scale Surface Geology of Australia dataset (2012 edition)

The file is an image created from magmap_v6_2015_VRTP, a Variable Reduction to Pole TMI grid of the Australian region with a grid cell spacing of ~3 seconds of arc (approximately 80 m). This image only includes airborne-derived TMI data for onshore and near-offshore continental areas. The VRTP processing followed Cooper and Cowan's (2005) differential reduction to pole up to 5th order polynomial. Magnetic inclination and declination were derived from the IGRF-11 geomagnetic reference model (Finlay et al., 2010) using a data representative date of January 2005 and elevation 300 m.

The Total Magnetic Intensity (greyscale) image is created from a composite TMI grid of the Australian region with a grid cell spacing of ~3 seconds of arc (approximately 80 m). This image only includes airborne-derived TMI data for onshore and near-offshore continental areas. Since the fifth edition was released in 2010 data from 41 new surveys have been added to the database, acquired mainly by the State and Territory Geological Surveys. It is estimated that 31 500 000 line-kilometres of survey data were acquired to produce the grid data, 4 500 000 line-kilometres more than for the previous edition. Details of the specifications of individual airborne surveys can be found in the Fourteenth Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). Matching of the grids in the database was achieved using a program called Gridmerge, which was originally developed within Geoscience Australia and has now been commercialised. This program was used to merge 41 new surveys to the 5th Edition Total Magnetic Intensity Anomaly Grid of Australia (Milligan et al., 2010). The 5th Edition merged 795 individual grids to create the compilation and to constrain long wavelengths, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of those survey grids which overlapped the AWAGS data (Milligan et al., 2009). As the 5th Edition was used as a base grid for the Gridmerge operation the new 6th Edition is essentially levelled to AWAGS. Individual and merged grids may be downloaded from the Geophysical Archive Data Delivery System (GADDS) on the Australian Government's Geoscience Portal at http://www.geoscience.gov.au/gadds. References: Milligan, P.R., Minty, B.R.S., Richardson, M. and Franklin, R., 2009. The Australia-wide Airborne Geophysical Survey - accurate continental magnetic coverage. Preview, 138, 70. Milligan, P.R., Franklin, R., Minty, B.R.S., Richardson, L.M. and Percival, P.J., 2010. Magnetic Anomaly Map of Australia (Fifth Edition), 1:5 000 000 scale, Geoscience Australia, Canberra. Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition). Geoscience Australia Record 2014/014.

Unfiltered Potassium element concentrations (percent K). The Radiometric Map of Australia dataset comprises gridsof potassium (K), uranium (U) and thorium (Th) element concentrations, and derivatives of these grids. This third edition was derived by seamlessly merging 45 new survey grids with the Second Edition Radiometric Map of Australia (Minty et al., 2010). Details of the specifications of individual airborne surveys can be found in the 2014 Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). Matching of the grids in the database was achieved using a program called Gridmerge, originally developed within Geoscience Australia and has now been commercialised. This program was used to merge 45 new surveys to the Second Edition Radiometric Map of Australia. The second edition merged over 550 individual grids to create the compilation (Minty et al., 2009), and the Australia-wide Airborne Geophysical Survey (AWAGS) airborne radiometric data was used to control the base levels of those survey grids which overlapped the AWAGS data (Milligan et al., 2009). As the second edition was used as a base grid for the Gridmerge operation the new Third Edition is essentially levelled to AWAGS. Filtering: Potassium, uranium, thorium and dose rate grids are available in both filtered and unfiltered versions. The low-pass filtering was achieved by applying a 7-point, degree-3 Savitzky-Golay filter (Savitzky and Golay, 1964) to each of the original survey grids prior to grid merging.