Norwegian geospatial services and solutions provider Blom has completed an aerial light detection and ranging (LiDAR) survey of 91km of rail track for railway development in Finland.
The survey was conducted for contractor VR Track because the Finnish rail constructor required digital ortho photos and DTMs (digital terrain models) for the planning of maintenance necessary to improve safety and traffic on the track.
The LiDAR survey was conducted along the main rail line across the Finnish towns of Lielahti and Kokemäki for an alliance of VR Track and the Finnish Traffic Authority.
VR Track's survey expert Pasi Kråknäs, who has managed the DTM project, said: "In my experience, TopEye technology produces very accurate and reliable laser data for this kind of modelling."
A LiDAR survey was conducted by flying a helicopter at a height of 400m, generating a point cloud of 10 points / m2, as well as digital images with ground resolution better than 5cm GSD (ground sample distance).
Despite the challenging weather conditions during that time, data collection was completed on 1 November 2011.
VR Track completed required control surveys for matching and calibration, while Blom Sweden processed LiDAR data and images, and quality control was completed by using Blom's in-house software TASQ.
A planning team at VR Track were handed the final project, with DTM covering a 100m wide corridor, digital ortho photos and a height model.
The company said that parts of the laser data were delivered to other consultants for additional vectoring work.