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Total Magnetic Intensity (TMI) Grid of Australia with Variable Reduction to Pole (VRTP) 2019 - seventh edition

Created 17/10/2025

Updated 17/10/2025

JSON format icon JSON RDF format icon RDF ISO19115-3 XML

Total magnetic intensity (TMI) data measures variations in the intensity of the Earth 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. A variable reduction to Pole is aimed at locating magnetic anomalies exactly above their source bodies and without any distortion. The 2019 Total magnetic Intensity (TMI) grid of Australia with variable reduction to pole (VRTP) 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. 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 of January 2005 and elevation 300 m.

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Field Value
Title Total Magnetic Intensity (TMI) Grid of Australia with Variable Reduction to Pole (VRTP) 2019 - seventh edition
Language English
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/3dcbe189-69d9-43c1-bb72-7d07be65f399
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        112.502532,
        -43.927315
      ],
      [
        154.661682,
        -43.927315
      ],
      [
        154.661682,
        -9.025662
      ],
      [
        112.502532,
        -9.025662
      ],
      [
        112.502532,
        -43.927315
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Total Magnetic Intensity (TMI) Grid of Australia with Variable Reduction to Pole (VRTP) 2019 - seventh edition". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/total-magnetic-intensity-tmi-grid-of-australia-with-variable-reduction-to-pole-vrtp-2019-sevent