How OS surveying is taking off

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.

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.