Airborne geophysical survey data

What it is and who has compiled it?

The Tellus South West airborne geophysical data was acquired during the second half of 2013. The survey comprised a high resolution magnetic/magnetic gradient survey combined with a multichannel (256 channel) radiometric survey.

The survey was carried out using 200 m (north–south) line separations at a mean elevation of 91 m. Encompassing the counties of Cornwall and parts of Devon and Somerset, the survey provided 60 323 line-kilometres of data.

What data is available and in what format?

Both magnetic and radiometric survey data are being made available. There are seven layers of magnetic information and seven layers of radiometric information. The user can download these as GeoTIFs (suitable for GIS applications) with a 40x40 m resolution.

How has it been processed and quality controlled (QC)?

The data have been fully QCed by both the contractor carrying out the geophysical survey and by BGS. The QC information alongside the standard airborne geophysical data processing applied to the dataset is provided in the BGS Report OR/14/014.

What were the particular methods and techniques used to collect the data?

Magnetism is measured from the aircraft by magnetic sensors which measure the perturbations in the Earth’s magnetic field created by the rock structure of the subsurface.

Natural and artificial radioactivity is measured using radiometric sensors (a gamma ray detector). All rocks and soils are very slightly radioactive with most terrestrial radiation coming from isotopes of uranium, thorium and potassium.

What terms and conditions apply to the data?

Geophysical maps and data are made available for download under the Open Government Licence, subject to the following acknowledgement accompanying the reproduced BGS materials: "Contains British Geological Survey materials © NERC [year]".

Research users should cite the data as follows in scientific or technical publications:

  • in the text: Beamish et al. 2014. (or similar)
  • in the reference list: Beamish, D, Howard, A S, Ward, E K, White, J, Young, M E. 2014. Tellus South West airborne geophysical data. Natural Environment Research Council, British Geological Survey.

How and where can I get the data from?

The maps with links to downloadable data can be viewed through the Tellus South West map viewer. Additional links to downloadable data are provided below. An open-file report that describes the acquisition and quality control of the airborne data is available to download. The data are also provided as WMS services.

The geophysical data comprise measurements of fields (magnetic and gamma-ray) rather than physical samples. The treatment and understanding of the data is usually provided by specialist interpretation and software. The Tellus South West team will be pleased to answer further questions relating to these data.

Download the data:

Are bespoke or raw datasets available if this isn’t suitable?

We can only supply full project area datasets and not cookie cuts for smaller areas. The ASCII data supplied are the industry standard method for storing and using fully processed airborne geophysical data. There is a web contact available on the metadata associated with each layer. We will make available to stakeholders the GeoTIFs and also the ASCII data used to generate the GeoTIFs.

Where can I get more information?

Please contact us by email to get more information on Tellus South West: TellusSW@nerc.ac.uk