The National Geophysical Grids web map service (WMS) will provide a collection of magnetic, gravity and radiometric grids derived from various geophysical measurements made over continental Australia. This particular release will include magnetic, gravity and radiometric grids constructed in 2019, and migrated grids from 2015.

The National Geophysical Grids web coverage service (WCS) will provide a collection of magnetic, gravity and radiometric grids derived from various geophysical measurements made over continental Australia. This particular release will include magnetic, gravity and radiometric grids constructed in 2019, and migrated grids from 2015.

This data collection are comprised of magnetic surveys acquired across Australia by Commonwealth, State and Northern Territory governments and the private sector with project management and quality control undertaken by Geoscience Australia. Magnetic surveying is a geophysical method for measuring the intensity (or strength) of the Earth's magnetic field, which includes the fields associated with the Earth's core and the magnetism of rocks in the Earth's crust. Measuring the magnetism of rocks, in particular, provides a means for the direct detection of several different types of mineral deposits and for geological mapping. The magnetism of rocks depends on the volume, orientation and distribution of their constituent magnetic minerals (namely magnetite, monoclinic pyrrhotite, maghaemite and ilmenite). The instrument used in magnetic surveys is a magnetometer, which can measure the intensity of the magnetic field in nanoteslas (nT). Magnetic surveys in this collection have been acquired using aircraft or ship-mounted magnetometers and are a non-invasive method for investigating subsurface geology.