Fast and Accurate Power Line Corridor Survey Using Spatial Line Clustering of Point Cloud

High-voltage and ultra-high-voltage overhead power lines are important to meet the electricity demand of our daily activities and productions. Due to the overgrowth of trees/vegetation within the corridor area, the distance between the power lines and its surroundings may break through the safety threshold, which could cause potential hazards such as discharge and fire. To ensure the safe and stable operation of the power lines, it is necessary to survey them regularly so that the potential hazards from the surroundings within the power line corridor could be investigated timely. This paper is motivated to quickly and accurately survey the power line corridor with the 3D point clouds. The main contributions of this paper include: (1) the spatial line clustering is proposed to accurately classify and complete the power line points, which can greatly overcome the sparsity and missing of LiDAR points within the complex power line corridor. (2) The contextual relationship between power lines and pylon is well investigated by the grid-based analysis, so that the suspension points of power lines on the pylon are well located. (3) The catenary plane-based simplification of 3D spatial distance calculation between power lines and ground objects facilitates the survey of the power line corridor. Experimental results show that the accuracy of safety distance surveying is 5 cm for power line corridors of all voltage levels. Compared to the ground-truth point-to-point calculation, the speed of surveying is enhanced thousands of times. It is promising to greatly improve both the accuracy and efficiency of surveying the potential hazards of power line corridor.

POWER LINE CORRIDORS IN PINE FORESTS AS HABITATS FOR GROUND BEETLES (COLEOPTERA, CARABIDAE) IN THE BELARUSIAN POOZERIE

For the first time in the Belarusian Lake District, the influence of regular tree felling in pine forests under power lines on the biodiversity of ground beetles has been studied. On the power line corridor species richness, number of individuals, and the diversity of ground beetles were highest in comparison with the adjacent forests (Pinetum vacciniosum and Pinetum myrtillosum). In addition, species composition and group of dominants composition were different. Among dominant species there are inhabitants of open spaces Poecilus versicolor and Calathus erratus. The assemblages of ground beetles of the power line corridor were the most differed from Pinetum vacciniosum. Regression analysis (GLM) showed a negative influence of the height of the herb-dwarf shrub layer on the number of individuals of ground beetles. Shrub cover positive affected carabid diversity, whereas soil moisture had a negative effect.

RADIOCARBON AND DENDROCHRONOLOGY APPLIED IN A LEGAL DISPUTE: A CASE FROM COLOMBIA

ABSTRACT In 2015 a dispute arose between an electricity company (EC) and smallholder of a teak plantation when the EC felled 80 trees (without consent of the owner) in a linear transect under a rural power-line-corridor (PLC), fragmenting the teak stand in two portions. The EC stated that there were no planted trees in the area when the PLC was established in 2008. The owner asserted he planted the stand in 2006 so in 2008 the company should have seen the planted trees. We used the bomb radiocarbon (14C) signal of three felled trees and dendrochronological dating of five trees, three felled by the EC and two felled by us in 2016, to do this study to determine the age. We found that the first growth rings were dated to 2005 both in the trees felled by the EC in 2015 and felled by us in 2016, one year before that reported by the owner (2006). This year corresponds to the wood present in the cuttings during the stand’s planting year. These facts are in agreement with the owner’s testimony. The plantation was 10 years old in 2015.

VOXEL-BASED EXTRACTION OF INDIVIDUAL PYLONS AND WIRES FROM LIDAR POINT CLOUD DATA

<p><strong>Abstract.</strong> Extraction of individual pylons and wires is important for modelling of 3D objects in a power line corridor (PLC) map. However, the existing methods mostly classify points into distinct classes like pylons and wires, but hardly into individual pylons or wires. The proposed method extracts standalone pylons, vegetation and wires from LiDAR data. The extraction of individual objects is needed for a detailed PLC mapping. The proposed approach starts off with the separation of ground and non ground points. The non-ground points are then classified into vertical (e.g., pylons and vegetation) and non-vertical (e.g., wires) object points using the vertical profile feature (VPF) through the binary support vector machine (SVM) classifier. Individual pylons and vegetation are then separated using their shape and area properties. The locations of pylons are further used to extract the span points between two successive pylons. Finally, span points are voxelised and alignment properties of wires in the voxel grid is used to extract individual wires points. The results are evaluated on dataset which has multiple spans with bundled wires in each span. The evaluation results show that the proposed method and features are very effective for extraction of individual wires, pylons and vegetation with 99% correctness and 98% completeness.</p>