Full description
Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's 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 data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.This GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic is a first vertical derivative of the Total Magnetic Intensity grid for the GSNSW Exploration NSW Area J, Cobar-Nymagee merge, 1999.
This grid has a cell size of 0.00049 degrees (approximately 50m). The grid has units of nanoTesla per km (or nT/km). The data used to produce the TMI grid was acquired in 1998 by the NSW Government, and consisted of 70181 line-kilometres of data at 250m line spacing and 60m terrain clearance. A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid.
Lineage
Maintenance and Update Frequency: notPlanned
Statement: This GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic is a first vertical derivative grid of the Total Magnetic Intensity (TMI) anomaly for the GSNSW Exploration NSW Area J, Cobar-Nymagee merge, 1999. The survey was acquired under the project No. 1354 for the geological survey of NSW. A total of 70181 line-kilometres of data at a line spacing of 250m and 60m terrain clearance were acquired to produce the TMI grid. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the Total Magnetic Intensity grid of the GSNSW Exploration NSW Area J, Cobar-Nymagee merge, 1999 survey to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. The processed data are checked by GA geophysicists using standard methods for assessing quality to ensure that the final data are fit-for-purpose. The grid has a cell size of 0.00049 degrees (approximately 50m). The grid has units of nanoTesla per km (or nT/km). The first vertical derivative grid is very helpful for the enhancement of near surface features and structural features such as faults and dykes. Details of the specifications of individual airborne surveys can be found in the Fourteenth Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). This Index is also available online at http://pid.geoscience.gov.au/dataset/79134.
References:
Intrepid Geophysics, http://www.intrepid-geophysics.com;
Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition).
Created: 07 03 2020
Issued: 07 03 2020
Modified: 05 07 2021
Data time period: 12 1998 to 31 07 1999
text: westlimit=145.4451; southlimit=-33.0413; eastlimit=147.0022; northlimit=-30.9828; projection=WGS84 (EPSG:4326)
Subjects
1vd |
Australia |
EARTH SCIENCES |
Earth sciences |
GADDS2.0 |
NCI |
NSW |
Published_External |
airborne digital data |
first vertical derivative |
geophysical survey |
geophysics |
geoscientificInformation |
grid |
mag |
magnetics |
magnetism |
palaeomagnetism |
raster |
survey 1354 |
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Other Information
The Geophysical Archive Data Delivery System (GADDS2) portal provides HTTP download of geophysics datasets in a number of formats. Point and line datasets are available in NetCDF and ASEG-GDF2. Grid datasets are available in NetCDF, GeoTIFF and ERS. (File available for download in various formats from the GADDS2 portal)
url :
https://portal.ga.gov.au/persona/gadds
File download for GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic (GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic file download)
NetCDF Subsetting Service (NCSS) for GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic (GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic NCSS)
OPeNDAP web service for GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic (GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic OPeNDAP)
OGC Web Mapping Service (WMS) for GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic (GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic WMS)
OGC Web Coverage Service (WCS) for GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic (GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic WCS)
GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic NCSS
GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic OPeNDAP
GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic WMS
GSNSW Exploration NSW Area J Cobar Nymagee magnetic first vd grid geodetic WCS
Identifiers
- URL : pid.geoscience.gov.au/dataset/ga/143326
- global : b1ef2579-2d9e-4b72-a5f4-a4ee643bac38
