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Gairdner - TMI RTP grid (AWAGS)

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 grid has a cell size of 0.0004 degrees (approximately 41m).The data are in nanoTesla (or nT). The data used to produce this grid was acquired in 2018 by the SA Government, and consisted of 104788 line-kilometres of data at 200m line spacing and 60m terrain clearance. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid. This survey grid is essentially levelled to AWAGS.The data has had a variable reduction to the pole applied to centre the magnetic anomaly over the magnetised body. The VRTP processing followed a differential reduction to pole calculation up to 5th order polynomial. Magnetic inclination and declination were derived from the IGRF-11 geomagnetic reference model using a data representative date and elevation representative of the survey.

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Additional Info

Field Value
Title Gairdner - TMI RTP grid (AWAGS)
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/a24978bf-07ce-4828-82b1-c8fd32b0d677
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 30/06/2018 - 23/01/2019
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        134.9936,
        -32.6849
      ],
      [
        136.5248,
        -32.6849
      ],
      [
        136.5248,
        -31.4805
      ],
      [
        134.9936,
        -31.4805
      ],
      [
        134.9936,
        -32.6849
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Gairdner - TMI RTP grid (AWAGS)". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/gairdner-tmi-rtp-grid-awags