How OS surveying is taking off

OS now has 24 UAS operators or drone pilots, complimenting over 200 surveyors across Great Britain who can mobilise quickly to capture landscape changes.

3 minute read
When a major landslide on the Isle of Wight took place, Ordnance Survey mobilised quickly to capture the impact, update the master map of Britain, and create a 3D model. With this view, local authorities were able to analyse the impact on property, infrastructure, and the natural environment.

OS now has 24 UAS operators or drone pilots, complimenting over 200 surveyors across Britain, as well as two planes, to capture landscape features. The UAS team flew 1,300 flights in 2023.

An average UAS flight will take 20 minutes and can survey sites that would normally take a field surveyor a whole day to cover. It works particularly well for new and larger sites like new build housing estates, wind and solar farm and golf courses.

UAS surveying offers the ability to mobilise quickly and fly all year round. There is also a safety aspect, because flying over a site means boots on the ground aren't required to cover difficult terrain or unstable ground such as a recent landslip. It’s also perfect for riskier projects such as busy roads, because its safer than having a surveyor walk a carriageway.

Following the initial landslip survey on the Isle of Wight, a second flight captured additional oblique imagery to build a 3D model. This gave impact analysis on vegetation, property, and infrastructure such as roads, water and gas, as well as the ability to consider which parts of the slope might slip next.

Aerial image of landslip at Ventor Isle of Wight
Landslip at Bonchurch on the Isle of Wight surveyed by an OS UAS operator

The timescale for capturing information to having it available in OS MasterMap layer can be three days. OS MasterMap is used for a wider range of customers including local authorities to look at property extents, footpaths, roads - and much more.

The UAS platforms that OS fly, connect to OS Net that provide up to 2-3 cm accuracy via a GPS correction. During a flight, the UAS takes images, that is then put into software which creates an orthomosaic - a large image where geometric distortion has been corrected to create a seamless mosaic dataset. The software can put lots of images and tie them together using a geo co-ordinate. Its possible to then drop this under OS MasterMap and adjust for any changes in the environment.

OS Rapid Mapping in action

Ordnance Survey plays a leading role in supporting location-based projects, both locally and internationally

For example, the Zambian government partnered with OS to rapidly build accurate maps of the capital, Lusaka. The city has undergone huge urban growth over recent years, including many large informal settlements which were entirely unmapped, and the mapping available at the time was not fit for purpose.

OS Rapid Mapping swiftly created accurate maps from satellite data, allowing the Zambian government to improve the quality of life of its citizens; by planning and delivering essential services, and assessing the risk from natural disaster in the new urban areas.

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Ordnance Survey
By Ordnance Survey

Our highly accurate geospatial data and printed maps help individuals, governments and companies to understand the world, both in Britain and overseas.

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