Magnetic Anomaly Grid Database of Australia (MAGDA)

• Summary
• MAGDA article (Preview 2004)
• Products
• Related links

Summary

An innovative approach to the compilation of magnetic grid data has led to the development of the Magnetic Anomaly Grid Database of Australia (MAGDA) at Geoscience Australia. MAGDA is a collection of mostly publicly available airborne magnetic grid data for on-shore and near-offshore Australia in which the flight-line magnetic data for each survey have been optimally gridded and the grids matched in one inverse process. New composite grids at 250 metre and 400 metre grid cell sizes form the basis of products known collectively as the Magnetic Anomaly Map of Australia (4th Edition, 2004).

In addition to the inclusion of new survey data, the 2004 edition of the map employs data from aeromagnetic traverses flown around Australia during 1990 and 1994. The traverse data are used for quality control of the grids they intersect and to constrain the grid merging process by forcing intersected grid data to the level of the traverse data.

MAGDA article (Preview 2004)

A full version of the article "A new generation Magnetic Anomaly Grid Database of Australia (MAGDA)" by P.R. Milligan, R. Franklin and D. Ravat, which appeared in the December 2004 Australian Society of Exploration Geophysicist's magazine Preview is available as a PDF document (1.71MB). Geoscience Australia acknowledges the Australian Society of Exploration Geophysicists (ASEG) for permission to use this article on the Geoscience Australia website.

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Products - maps, grids and images

A number of free download products are available to provide an efficient, streamlined the production of the Magnetic Anomaly Map of Australia (4th Edition, 2004). They are:

• a 1:25 million scale hardcopy map, A4 size downloaded as a printable version (PDF 491KB), or as a preview image (JPEG 331KB);
• a 1:5 million scale hardcopy map, A0 size downloaded as a printable version (PDF 3.91MB), or as a preview image (JPEG 3.74MB); and
• grid and image data, which can be downloaded via the Geophysical Archive Data Delivery System (GADDS):
• total magnetic intensity grid - onshore only (250 metre cell size);
• total magnetic intensity grid - onshore plus marine data (400 metre cell size);
• first vertical derivative grid of total magnetic intensity, 4-byte real (250 metre cell size); and
• first vertical derivative greyscale image of total magnetic intensity (250 metre cell size).

Note: Open file magnetic grid data and line data used in the production of the Magnetic Anomaly Map of Australia may be downloaded free of charge via GADDS.

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Related links

• Geophysics home page
• Continental Geophysics
• Australian Fundamental Gravity Network (AFGN)
• Seismic Acquisition and Processing
• AEM Acquisition and Interpretation
• Magnetic Anomaly Grid Database of Australia (MAGDA)
• Airborne Geophysics and Gravity Data
• Gravimetry
• A transect through central Australia