Product catalogue
Total Magnetic Intensity Grid of Australia 2019 - First Vertical Derivative (1VD)
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 first vertical derivative (1VD) grid is derived from the 2019 Total magnetic Intensity (TMI) grid of Australia which has a grid cell size of ~3 seconds of arc (approximately 80 m). As the vertical derivative filter is essentially a high-pass filter, longer wavelengths are suppressed, and shorter wavelengths emphasized. The magnetic units of the data are in nT per metre.
Simple
Identification info
- Date (Publication)
- 2019-11-04T00:00:00
- Date (Revision)
- 2019-11-20T00:38:22
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/132275
- Citation identifier
- Digital Object Identifier/http://dx.doi.org/10.26186/5dd48b1368ece
- Cited responsible party
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Role Organisation / Individual Name Details Publisher Geoscience Australia
Canberra Author Poudjom Djomani, Y.
Co-author Minty, B.R.S.
- 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
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- 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
- Theme
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Vertical Derivative
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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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- 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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first vertical derivative
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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
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Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
- 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) [4.7 GB]
Download the data (ers) [4.7 GB]
- Distribution format
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ers
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Resource lineage
- Statement
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The first vertical derivative (1VD) is derived from the 2019 Total Magnetic Intensity (TMI) grid of the Australian region. The TMI grid 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 first vertical derivartive (1VD) grid was produced in two steps. The TMI grid was first transformed to a Lambert Conic Conformal projection before applying a standard implementation of the vertical derivative process in the frequency domain, and then conversion back to a geodetic coordinate system. As the vertical derivative filter is essentially a high-pass filter, longer wavelengths are suppressed, and shorter wavelengths emphasized. The magnetic units of the data are in nT per metre.
References
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 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
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Australian Government Security ClassificationSystem
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
Metadata
- Metadata identifier
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urn:uuid/77fccb44-c2d2-468b-bfb9-fd21b6030661
- Title
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GeoNetwork UUID
- Contact
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Point of contact Poudjom Djomani, Y.
- Title
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Geophysical Data Collection - magnetics
- Date (Creation)
- 1951-01-01T00:00:00
- Edition date
- 1951-01-01T00:00:00
Identifier
- Description
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UUID
Identifier
- Description
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eCat ID
Type of resource
- Resource scope
- Dataset
- Name
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dataset
Alternative metadata reference
- Title
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Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/132275
- 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