A HANDHELD mobile laser scanner is helping researchers in New Zealand develop new working practices to characterize forest stands for management and research purposes. The team at Scion, a New Zealand Crown Research Institute, required a practical means for accurately locating and measuring individual trees. Using ZEB1 they achieved significant advantages in speed of data capture, quality of the resulting point cloud and ease of use of the system.
Scion purchased the ZEB1 from 3D Laser Mapping, following successful trials. ZEB1 uses robotic technology called Simultaneous Localization and Mapping (SLAM). It was developed by Australia’s national science agency CSIRO.
“Traditionally poor GPS under forest cover makes identifying trees a problem,” says Scion’s David Pont, an award-winning scientist who specializes in research to identify individual trees from remotely sensed aerial LiDAR. “The ability of ZEB1 to provide the position for spatial locations using SLAM technology – specifically developed for mapping of areas with no GPS – was of immediate interest to us.”
3D Laser Mapping trialled ZEB1, scanning small stands of trees close to the Scion campus in Rotorua, New Zealand. Within hours the team was back in the office viewing a highly detailed point cloud of the trees. Having subsequently purchased their own ZEB1, researchers at Scion are carrying out further trials of the system including scanning inventory plots used to characterize forest stands for management purposes. The project team aims to extract tree diameters, locations and stem shapes from the ZEB1 point clouds rather than through the use of conventional manual measurements.
“Besides portability and ease of use, the ZEB1 shines in the speed of scanning,” says David Pont. “In forests, trees are obscured by terrain, undergrowth and even other trees and conventional tripod units require multiple scans and registration of the point cloud to cover any significant area. ZEB1 scans continuously as you move around to provide a single, registered point cloud. It is this ability to scan as you move that lifts the use of the ZEB1 from an academic exercise to something that demonstrates real potential for practical forestry applications.”