Modelling our landscape in 3D
3D model of cliff face at Aldbrough
9 August 2016 by Tom Marshall
Unmanned aerial vehicles (UAVs) are helping NERC's British Geological Survey (BGS) understand and monitor areas that are susceptible to landslides around the UK, allowing the authorities to manage risks to the public more effectively.
BGS researchers use a range of UAVs including a six-rotor model known as the HexaKopter, which flies slowly around the landslide, taking many overlapping photos from different angles. They then use a computer to stitch these images together into a 3D model of the cliff face.
The HexaKopter can carry heavier instruments and fly in nastier weather than more common four-rotor models. "Wind's a big issue for us," says Dr Colm Jordan, who leads the BGS Earth and Planetary Observation and Monitoring team. "If you're going out in the immediate aftermath of a landslide, the weather's usually not ideal. So you need a platform that can handle the conditions."
UAVs can respond quickly when a major new landslide is reported. The team doesn't only visit landslides right after they've happened, though; by returning regularly, they can build up a picture of how an area is changing over time. The 3D data is combined with analysis of the area's geology, and with readings from other on-site instruments like soil moisture meters and GPS sensors.
For instance, the team keep a close eye on the cliffs at Aldbrough in Yorkshire, which are receding quickly and have already destroyed several buildings. Much of this can be done in other ways, but that would take longer. "Having the drone lets us use the people on the ground in a more focused way; they don't have to do the basic work of creating a model of the whole hillside," says Jordan. "So they can concentrate on hotspots of activity where things are changing particularly fast."
BGS drones don't only work on landslides; they're involved in projects that range from monitoring for gas that's leaking into the atmosphere from the ground to understanding how Icelandic glaciers are responding to climate change.