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Spencer - TMI grid (AWAGS)

Created 17/10/2025

Updated 17/10/2025

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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 Spencer - TMI grid (AWAGS) has a cell size of 0.0004 degrees (approximately 41m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2018 by the SA Government, and consisted of 49937 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.

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Additional Info

Field Value
Title Spencer - TMI grid (AWAGS)
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/en/dataset/9a840513-34d2-4227-8598-db336620a8f2
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 11/06/2018 - 11/06/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        136.491,
        -32.6702
      ],
      [
        137.913,
        -32.6702
      ],
      [
        137.913,
        -31.9954
      ],
      [
        136.491,
        -31.9954
      ],
      [
        136.491,
        -32.6702
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

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