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Magnetic Anomaly Map of Australia, Seventh Edition, 2020 - Enhanced Products Package - TMI RTP 0.5VD grid

Created 16/10/2025

Updated 16/10/2025

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Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. 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. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This Magnetic Anomaly Map of Australia, Seventh Edition, 2020 - Enhanced Products Package - TMI RTP 0.5VD grid is a half vertical derivative of the Total Magnetic Intensity grid for the Magnetic Anomaly Map of Australia, Seventh Edition, 2019. The 2019 Total magnetic Intensity (TMI) grid of Australia has a grid cell size of ~3 seconds of arc (approximately 80 m). This grid only includes airborne-derived TMI data for onshore and near-offshore continental areas. Since the sixth edition was released in 2015, data from 234 new surveys have been added to the database, acquired mainly by the State and Territory Geological Surveys. The new grid was derived from a re-levelling of the national magnetic grid database. The survey grids were levelled to each other, and to the Australia Wide Airborne Geophysical Survey (AWAGS), which serves as a baseline to constrain long wavelengths in the final grid. It is estimated that 33 500 000 line-kilometres of survey data were acquired to produce the 2019 grid data, about 2 000 000 line-kilometres more than for the previous edition. The grid has units of nanoTesla per km (or nT/km). The RTP processing followed a differential reduction to pole calculation up to 5th order polynomial. Magnetic inclination and declination were derived from the IGRF-15 geomagnetic reference model using a data representative date and elevation representative of the survey. A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the half vertical derivative grid.

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Field Value
Title Magnetic Anomaly Map of Australia, Seventh Edition, 2020 - Enhanced Products Package - TMI RTP 0.5VD grid
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/d40a98b9-7b27-47ff-b8aa-36c7ef8431a7
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 01/01/2019 - 31/12/2019
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        105.9996,
        -43.9301
      ],
      [
        154.6635,
        -43.9301
      ],
      [
        154.6635,
        -9.0265
      ],
      [
        105.9996,
        -9.0265
      ],
      [
        105.9996,
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      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Magnetic Anomaly Map of Australia, Seventh Edition, 2020 - Enhanced Products Package - TMI RTP 0.5VD grid". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/magnetic-anomaly-map-of-australia-seventh-edition-2020-enhanced-products-package-tmi-rtp-0-5vd-1