The thorium over potassium grid is a derivative of the 2015 radiometric or gamma-ray grid of Australia. The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data are collected on airborne geophysical surveys conducted by Commonwealth, State and Northern Territory Governments and the private sector.
The 2015 thorium over potassium grid has a cell size of about 100m (0.001 degrees) and is derived from the filtered thorium and potassium grids.
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The thorium over potassium ratio grid is a derivative of the 2015 radiometric or gamma-ray grid of Australia. The radiometric grid of Australia is derived by merging over 550 airborne gamma-ray spectrometric surveys by the Commonwealth, State and Territory Governments and held in the national radioelement database of Australia. The cell sizes of the original survey grids range from 50 m through 800 m, but most have a cell size of about 100 m. The original survey grids were levelled and then re-sampled to generate the Radiometric Map of Australia Grids with a cell size of about 100m (0.001 degrees).
The data quality varies depending on the survey. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface.
Thorium over potassium ratio grid was calculated after first applying a low value Â¿clipÂ¿ to the thorium and potassium grid values Â¿ i.e. any values less than 0.1 are set to 0.1 prior to ratioing. This clipping will necessarily introduce some artefacts into the ratio grids in areas of very low radioelement concentrations.The final grid is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.
The original grid was converted from ERMapper (.ers) format to netCDF4_classic format using GDAL1.11.1. The main purpose of this conversion is to enable access to the data by relevant open source tools and software. The netCDF grid was created on 2016-03-29.
20170906 NetCDF file restructured to be indexed Southward-positive for improved performance and interoperability
Geophysical Data Collection - radiometrics
UUID - c6b58f54-102d-19e9-e044-00144fdd4fa6,
eCat ID - 74513
WGS 84 (geocentric) (EPSG:4328)
Downloads and Links
NetCDF file download via HTTP for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
NCSS for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
Zipped ERS file download via HTTP for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
OPeNDAP service for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
WCS for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
WMS for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
Digital Object Identifier for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
Australian Geophysical Archive Data Delivery System
NetCDF file on NCI filesystem for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
THREDDS catalog page for dataset 221dcfd8-04f8-5083-e053-10a3070a64e3
The radiometric grid of Australia is derived by merging over 550 airborne gamma-ray spectrometric surveys by the Commonwealth, State and Territory Governments and held in the national radioelement database of Australia.