Product catalogue
Total Magnetic Intensity (TMI) Grid of Australia with Variable Reduction to Pole (VRTP) 2019 - seventh edition
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.
Simple
Identification info
- Date (Creation)
- 2019-11-01T00:00:00
- Date (Publication)
- 2019-11-20T00:18:37
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/131519
- Citation identifier
- Digital Object Identifier/http://dx.doi.org/10.26186/5e9cf2e3477e8
- 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.
- Point of contact
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Resource provider Resources Division
Point of contact Poudjom Djomani, Y.
- 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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RTP
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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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reduction to pole
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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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- Feature type
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raster
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- Service
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GADDS2.0
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- Theme
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TMI
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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
-
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
Associated resource
- Association Type
- Operated on by
- Title
-
National Magnetic And Radiometric Grids WCS
- Citation identifier
- 146015
- Citation identifier
- e49f3b62-01c3-474c-b731-ad35c69fe72d
- 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 the data (ers) [4.6 GB]
Download the data (ers) [4.6 GB]
- Distribution format
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ers
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- OnLine resource
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National Magnetic And Radiometric Grids WMS
National Magnetic And Radiometric Grids WMS
- Distribution format
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OGC:WMS
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- OnLine resource
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National Magnetic And Radiometric Grids WCS
National Magnetic And Radiometric Grids WCS
- Distribution format
-
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OGC:WCS
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Resource lineage
- Statement
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The variable reduction to Pole (VRTP) grid of Australia is processed from the 2019 TMI grid of the Australian region. The TMI grid is the seventh edition magnetic grid 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 data, 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 VRTP processing followed Cooper and Cowan's (2005) differential reduction to pole up to 5th order polynomial. Magnetic inclination and declination were derived from the IGRF-11 geomagnetic reference model (Finlay et al., 2010) using a data representative date of January 2005 and elevation 300 m.
References
Cooper, G.R.J., Cowan, D.R., 2005. Differential reduction to the pole, Computers & Geosciences, Vol. 31, Issue 8, pp. 989-999.
Finlay, C.C., Maus, S., Beggan, C.D., Bondar, T. N., Chambodut, A., Chernova, T.A., Chulliat, A., Golovkov, V.P., Hamilton, B., Hamoudi, M., Holme, R., Hulot, G., Kuang, W., Langlais, B., Lesur, V., Lowes, F.J. Lühr, H., Macmillan, S., Mandea, M., McLean, S., Manoj, C., Menvielle, M., Michaelis, I., Olsen, N., Rauberg, J., Rother,M., Sabaka, T.J., Tangborn, A., Tøffner-Clausen, L., Thébault, E., Thomson, A.W.P., Wardinski, I., Wei1, Z. and Zvereva, T.I., 2010. International Geomagnetic Reference Field: the eleventh generation, Geophysical Journal International, vol. 183, pp. 1216-1230.
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.
- Hierarchy level
- Dataset
- Description
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The variable reduction to Pole (VRTP) grid was processed from the 2015 Total Magnetic Intensity (TMI) grid of the Australia region. The later grid 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/c32a7e89-d4b4-4eeb-b0c0-0c2d572fe5d7
- 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
Type of resource
- Resource scope
- Dataset
- Name
-
dataset
Alternative metadata reference
- Title
-
Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/131519
- 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
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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