Product catalogue
Total Magnetic Intensity (TMI) Grid of Australia 2019 - seventh edition - 80 m cell size
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.
The 2019 Total magnetic Intensity (TMI) grid of Australia 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.
Since the sixth edition was released in 2015, data from 234 new surveys have been added to the database, acquired mainly by the State and Territory Geological Surveys. The new grid was derived from a re-levelling of the national magnetic grid database. The survey grids were levelled to each other, and to the Australia Wide Airborne Geophysical Survey (AWAGS), which serves as a baseline to constrain long wavelengths in the final grid. It is estimated that 33 500 000 line-kilometres of survey data were acquired to produce the 2019 grid data, about 2 000 000 line-kilometres more than for the previous edition.
Simple
Identification info
- Date (Creation)
- 2019-11-04T00:00:00
- Date (Publication)
- 2019-11-20T02:48:22
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/131505
- Citation identifier
- Digital Object Identifier/http://dx.doi.org/10.26186/5e9cf3f2c0f1d
- Cited responsible party
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Role Organisation / Individual Name Details Publisher Geoscience Australia
Canberra Author Poudjom Djomani, Y.
Author Minty, B.R.S.
Author Hutchens, M.
Author Lane, R.J.L.
- Point of contact
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Role Organisation / Individual Name Details Custodian Commonwealth of Australia (Geoscience Australia)
Voice Point of contact Poudjom Djomani, Y.
Resource provider Resources Division
- Topic category
-
- Geoscientific information
Extent
))
- Maintenance and update frequency
- Not planned
Resource format
- Title
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Product data repository: Various Formats
- Website
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Data Store directory containing the digital product files
Data Store directory containing one or more files, possibly in a variety of formats, accessible to Geoscience Australia staff only for internal purposes
- Keywords
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HVC_144635
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- Theme
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TMI
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- Theme
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magnetics
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- Australian and New Zealand Standard Research Classification (ANZSRC)
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magnetism and palaeomagnetism
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- Theme
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airborne digital data
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- Theme
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national geophysical compilation
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- Discipline
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Earth sciences
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- Discipline
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geophysics
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- Data centre
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NCI
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- Place
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Australia
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- Feature type
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grid
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- Keywords
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Published_External
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- Service
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GADDS2.0
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- Theme
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geophysical survey
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- Theme
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Total Magnetic Intensity
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- Temporal
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2019
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Resource constraints
- Title
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Creative Commons Attribution 4.0 International Licence
- Alternate title
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CC-BY
- Edition
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4.0
- Access constraints
- License
- Use constraints
- License
Resource constraints
- Title
-
Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
Associated resource
- Association Type
- Operated on by
- Title
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National Magnetic And Radiometric Grids WMS
- Citation identifier
- 140126
- Citation identifier
- 9bac39d0-827c-4ca8-9f15-f99c1c201b64
- Language
- English
- Character encoding
- UTF8
Distribution Information
- Distributor contact
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Role Organisation / Individual Name Details Distributor Commonwealth of Australia (Geoscience Australia)
Voice
- OnLine resource
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Download Portland Smelter Anomaly Removal Report (pdf) [110.9 KB]
Download Portland Smelter Anomaly Removal Report (pdf) [110.9 KB]
- Distribution format
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pdf
- File decompression technique
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nil
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- OnLine resource
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Download Merging of Magnetic Survey Data Report (pdf) [2.09 MB]
Download Merging of Magnetic Survey Data Report (pdf) [2.09 MB]
- Distribution format
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pdf
- File decompression technique
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nil
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- OnLine resource
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Download the Data (ers) [4.6 GB]
Download the Data (ers) [4.6 GB]
- Distribution format
-
-
ers
- File decompression technique
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nil
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- OnLine resource
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Download combined Hue, Saturation, Intensity (HSI) color image (GeoTIFF) [896.63 MB]
Download combined Hue, Saturation, Intensity (HSI) color image (GeoTIFF) [896.63 MB]
- Distribution format
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zip
- File decompression technique
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unzip
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- OnLine resource
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National Magnetic And Radiometric Grids WMS
National Magnetic And Radiometric Grids WMS
- Distribution format
-
Resource lineage
- Statement
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The 2019 magnetic grid of the Australian region is the seventh edition with a 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. Since the sixth edition was released in 2015, data from 234 new surveys have been added to the database, acquired mainly by the State and Territory Geological Surveys. It is estimated that 33 500 000 line-kilometres of survey data were acquired to produce the 2019 grid, about 2 000 000 line-kilometres more than for the previous edition.
The 2019 magnetic grid was derived from a complete re-levelling of the national magnetic grid database. The survey grids were levelled to each other, and to the Australia Wide Airborne Geophysical Survey (AWAGS) (Milligan et al., 2009), which serves as a baseline to constrain long wavelengths in the final grid. The levelling and grid-merging procedure was described in detail in Minty et al. (2003). The new 2019 map compilation is comprised of a merge of 1059 survey grids. The addition of almost a decade’s worth of new high-quality surveys adds significantly to the 2010 and 2015 versions of the map.
Further processing was applied to the original TMI grid to reduce the magnetic effect of the Portland Smelter Complex (PSC). The anomaly associated with the complex can have erroneous effects on products created using Fourier domain processing of the grid. A subset of the TMI grid covering the area of the PSC was cut for easy processing. Filling of the grid was done in MATLAB using function 'inpaintn' from Garcia (2020), based on Wang et al. (2012). This procedure resulted in an anomaly of +100nT in the region of the PSC. Further, a cosine averaging filter was applied to the PSC and its edges to remove the short wavelength anomalies which may lead to misinterpretation of the data. The processed subset grid was then overlain onto the national TMI grid as a final product.
References:
Garcia, D., 2020. Inpaint over missing data in 1-D, 2-D, 3-D, ... nd arrays https://www.mathworks.com/matlabcentral/fileexchange/27994-inpaint-over-missing-data-in-1-d-2-d-3-d-nd-arrays), MATLAB Central File Exchange.
Milligan, P.R., Minty, B.R.S., Richardson, M. and Franklin, R., 2009. The Australia-wide Airborne Geophysical Survey accurate continental magnetic coverage. Preview, No. 138, p. 1-128.
Minty, B.R.S., Milligan, P.R., Luyendyk, A.P.J. and Mackey, T., 2003. Merging airborne magnetic surveys into continental-scale compilations. Geophysics, 68 (3), 988-995.
Wang, G., Garcia, D., Liu, Y., de Jeu, R. and Dolman, A.J., 2012, A three-dimensional gap filling method for large geophysical datasets: Application to global satellite soil moisture observations: Environmental Modelling Software, 30, 139-142, doi: 10.1016/j.envsoft.2011.10.015.
- Hierarchy level
- Dataset
- Description
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The 2015 Total Magnetic Intensity (TMI) grid of the Australia region is made of a compilation of 31,500,000 line-kilometres of survey data acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations.
Reference System Information
- Reference system identifier
- EPSG/GDA94 (EPSG:4283)
Metadata constraints
- Title
-
Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
Metadata
- Metadata identifier
-
urn:uuid/f2e58161-24cf-42d2-b328-a9039f72113b
- Title
-
GeoNetwork UUID
- Contact
-
Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Point of contact Poudjom Djomani, Y.
- Title
-
Geophysical Data Collection - magnetics
- Date (Creation)
- 1951-01-01T00:00:00
- Edition date
- 1951-01-01T00:00:00
Identifier
- Description
-
UUID
Identifier
- Description
-
eCat ID
Type of resource
- Resource scope
- Dataset
- Name
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dataset
Alternative metadata reference
- Title
-
Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/131505
- Date info (Revision)
- 2018-04-20T06:00:17
- Date info (Creation)
- 2015-01-27T00:00:00
Metadata standard
- Title
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AU/NZS ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-1:2014
Metadata standard
- Title
-
ISO 19115-3
- Title
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Geoscience Australia Community Metadata Profile of ISO 19115-1:2014
- Edition
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Version 2.0, September 2018
- Citation identifier
- https://pid.geoscience.gov.au/dataset/ga/122551