Data

5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied

Geoscience Australia

Geophysical Acquisition & Processing Section

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ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rfr_id=info%3Asid%2FANDS&rft_id=info:doi10.26186/150994&rft.title=5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied&rft.identifier=10.26186/150994&rft.publisher=Commonwealth of Australia (Geoscience Australia)&rft.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 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied is the first vertical derivative of the TMI RTP grid of the Narryer survey.This grid has a cell size of degrees (approximately 20m) , and given in units of nT per metre (nT/m). The data used to produce the TMI grid was acquired in 2024 by the WA Government, and consisted of 415090 line-kilometres of data at 100m line spacing and 50m terrain clearance. The data has had a variable reduction to the pole applied to centre the magnetic anomaly over the magnetised body. 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 and elevation representative of the survey. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the TMI RTP grid of the Narryer survey to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. This grid shows the magnetic response of subsurface features with contrasting magnetic susceptibilities. The grid can also be used to locate structural features such as dykes.Maintenance and Update Frequency: asNeededStatement: This 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied is the first vertical derivative grid of an airborne-derived Total Magnetic Intensity (TMI) Reduced to the Pole (RTP) grid for the Narryer survey. The survey was acquired under the project No. 5028 for the geological survey of WA. A total of 415090 line-kilometres of data at a line spacing of 100m were acquired to produce the TMI grid. The data has had a variable reduction to the pole applied to centre the magnetic anomaly over the magnetised body. 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 and elevation representative of the survey. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the TMI RTP grid of the Narryer survey to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. The image shows the magnetic response of subsurface features with contrasting magnetic susceptibilities. The image can also be used to locate structural features such as 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 Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition). Intrepid Geophysics http://intrepid-geophysics.com&rft.creator=Geophysical Acquisition & Processing Section &rft.date=2026&rft.coverage=westlimit=115.99191161173253; southlimit=-25.861845684704544; eastlimit=116.86334459404108; northlimit=-24.98637259160062; projection=GDA94 (EPSG:4283)&rft.coverage=westlimit=115.99191161173253; southlimit=-25.861845684704544; eastlimit=116.86334459404108; northlimit=-24.98637259160062; projection=GDA94 (EPSG:4283)&rft_rights=Creative Commons Attribution 4.0 International Licence https://creativecommons.org/licenses/by/4.0/&rft_rights=© Commonwealth of Australia (Geoscience Australia) and State of Western Australia (Department of Mines, Industry Regulation and Safety) 2026&rft_rights=Australian Government Security Classification System https://www.protectivesecurity.gov.au/publications-library/policy-8-classification-system&rft_subject=geoscientificInformation&rft_subject=EARTH SCIENCES&rft_subject=NCI&rft_subject=Earth sciences&rft_subject=geophysics&rft_subject=grid&rft_subject=Australia&rft_subject=WA&rft_subject=survey 5028&rft_subject=GADDS2.0&rft_subject=TMI&rft_subject=magnetics&rft_subject=magnetism&rft_subject=palaeomagnetism&rft_subject=airborne digital data&rft_subject=geophysical survey&rft_subject=mag&rft_subject=total magnetic intensity&rft_subject=reduced to the pole&rft_subject=RTP&rft_subject=first vertical derivative&rft_subject=1VD&rft_subject=greyscale&rft_subject=image&rft_subject=Published_External&rft.type=dataset&rft.language=English Access the data

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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 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied is the first vertical derivative of the TMI RTP grid of the Narryer survey.
This grid has a cell size of degrees (approximately 20m) , and given in units of nT per metre (nT/m). The data used to produce the TMI grid was acquired in 2024 by the WA Government, and consisted of 415090 line-kilometres of data at 100m line spacing and 50m terrain clearance. The data has had a variable reduction to the pole applied to centre the magnetic anomaly over the magnetised body. 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 and elevation representative of the survey. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the TMI RTP grid of the Narryer survey to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. This grid shows the magnetic response of subsurface features with contrasting magnetic susceptibilities. The grid can also be used to locate structural features such as dykes.

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Maintenance and Update Frequency: asNeeded

Statement: This 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied is the first vertical derivative grid of an airborne-derived Total Magnetic Intensity (TMI) Reduced to the Pole (RTP) grid for the Narryer survey. The survey was acquired under the project No. 5028 for the geological survey of WA. A total of 415090 line-kilometres of data at a line spacing of 100m were acquired to produce the TMI grid. The data has had a variable reduction to the pole applied to centre the magnetic anomaly over the magnetised body. 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 and elevation representative of the survey. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the TMI RTP grid of the Narryer survey to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. The image shows the magnetic response of subsurface features with contrasting magnetic susceptibilities. The image can also be used to locate structural features such as 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 Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition). Intrepid Geophysics http://intrepid-geophysics.com

Notes

Purpose
Magnetic and radiometric data are types of geophysical information primarily used to map geology. The data will have applications in mineral, energy, and groundwater exploration as well as environmental studies.

Issued: 05 05 2026

Data time period: 2026-02-25 to 2026-02-25

This dataset is part of a larger collection

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text: westlimit=115.99191161173253; southlimit=-25.861845684704544; eastlimit=116.86334459404108; northlimit=-24.98637259160062; projection=GDA94 (EPSG:4283)

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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 External Link

File download for 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied (5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied file download)

url : https://thredds.nci.org.au/thredds/fileServer/iv65/Geoscience_Australia_Geophysics_Reference_Data_Collection/airborne_geophysics/WA/grid/P5028/P5028_3_TMI_reduced_RTP_1VD.nc External Link

NetCDF Subsetting Service (NCSS) for 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied (5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied NCSS)

url : https://thredds.nci.org.au/thredds/ncss/grid/iv65/Geoscience_Australia_Geophysics_Reference_Data_Collection/airborne_geophysics/WA/grid/P5028/P5028_3_TMI_reduced_RTP_1VD.nc/dataset.html External Link

OPeNDAP web service for 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied (5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied OPeNDAP)

url : https://thredds.nci.org.au/thredds/dodsC/iv65/Geoscience_Australia_Geophysics_Reference_Data_Collection/airborne_geophysics/WA/grid/P5028/P5028_3_TMI_reduced_RTP_1VD.nc.html External Link

OGC Web Mapping Service (WMS) for 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied (5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied WMS)

url : https://thredds.nci.org.au/thredds/wms/iv65/Geoscience_Australia_Geophysics_Reference_Data_Collection/airborne_geophysics/WA/grid/P5028/P5028_3_TMI_reduced_RTP_1VD.nc?service=WMS&version=1.3.0&request=GetCapabilities External Link

OGC Web Coverage Service (WCS) for 5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied (5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied WCS)

url : https://thredds.nci.org.au/thredds/wcs/iv65/Geoscience_Australia_Geophysics_Reference_Data_Collection/airborne_geophysics/WA/grid/P5028/P5028_3_TMI_reduced_RTP_1VD.nc?service=WCS&version=1.0.0&request=GetCapabilities External Link

5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied NCSS

5028 Block 3 (Northwest) Grid of Total Magnetic Intensity (TMI) with Reduction to Pole (RTP) and a First Vertical Derivative (1VD) applied OPeNDAP