National Gravity Compilation 2019: Airborne DGIR Tilt Grid for Australia

Geoscience Australia's 2019 National Gravity Compilation includes a de-trended global isostatic residual (DGIR) tilt grid derived from approximately 1.8 million gravity observations. The grid combines ground data from the Australian National Gravity Database, 345,000 line km of airborne gravity, and 106,000 line km of airborne gravity gradiometry, with a cell size of about 435 meters. Data were acquired from the 1940s onward by government, industry, and research organizations.

Use Cases

• Detect edges of geological units based on the tilt filter derived from gravity anomalies.
• Model subsurface density structures based on de-trended global isostatic residual (DGIR) anomalies.
• Improve geological mapping resolution in areas with sparse ground data using integrated airborne gravity and gradiometry surveys.
• Analyze continental-scale geological features over Australia and its margins using the 0.00417-degree resolution grid.

Strengths

• Integrates a large volume of observations, including nearly 1.4 million ground stations and over 450,000 line km of airborne surveys.
• Data quality is checked by GA geophysicists to ensure it is fit-for-purpose.
• Combines multiple data sources (ground, airborne, offshore) from the 1940s to 2019 for comprehensive coverage.
• Provides high-resolution data with ground station spacing as low as 1 km and airborne line spacing as low as 0.5 km.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Data freshness should be verified as the underlying observations are current only as of September 2019.
• The dataset may reflect geographic bias, with variable station density across the continent.

Provenance

Source

Geoscience Australia Data, supplemented by offshore data from Scripps Institution of Oceanography, NOAA, and NGA.

Collection Method

Processed from ground observations, airborne gravity, and gravity gradiometry data using standard geophysical methods and a fast Fourier transform (FFT) tilt filter.

Time Range

1940s to 2019

Freshness

Last updated 2026-04-30 12:36:55.401691; underlying observations current as of September 2019.

Geography

Australia and its continental margins