Topographic, UAV and 3D Laser Scanning
A challenging project, due to the very narrow underground culvert, just 900mm in places. We undertook a 3D laser scan below ground to capture a point cloud, and geo-referenced the data to OSGM15.
Case Study in Detail
It was a tight squeeze at times…! However, our team of surveyors found a way to deliver the results safely for the client, on this culvert 3D laser scanning project.
A borough council in Wales commissioned us to undertake a 3D laser scan of a culvert, as part of their ongoing asset management programme. We have worked with the council on several previous occasions to deliver laser scanning and multidisciplinary work, following the recommendation of another client; so the council knew they could trust our professionalism and deliverables.
On this occasion we were commissioned to undertake work both above and below ground. We began by installing control and traversing around the site using our SX10 total station to ensure we obtained the highest level of geographical positioning accuracy. We then completed a UAV survey using our Phantom 4 Pro Drone to give a true colour overview of the survey area.
Below ground our Faro laser scanner traversed up through the culvert using strategically placed targets, we captured a black and white point cloud which was then accurately geo-referenced to the above ground data.
The challenge came due to the narrowness of the culvert, just 900mm wide for a significant part of its length. However, once the targets were in position the working space for our two surveyors and equipment was reduced to just 700mm. To ensure good health and safety practice, we engaged the support of Edwards Diving Services (EDS) Ltd, who had specially trained confined space rescue teams on standby.
Thankfully the two-day project was completed without incident by our survey team, which comprised Jake, Sarah, Georgia and Tom.
By combining the datasets from the topographic and underground surveys we were able to create one homogeneous 3D deliverable for the client, enabling them to have a complete, integrated record of the area as a basis for decision making and future work.