Case Study: How We Surveyed 15 km of High-Voltage Power Lines Without Setting Foot on the Ground
As part of a planning application for a solar farm development, Drone Services Ireland was engaged to survey approximately 15 km of 220 kV and 110 kV overhead power lines adjacent to the proposed panel installation area. The project required accurate positional data for every transmission pole, conductor span, sag point, and ground clearance, together with a topographical survey of the fields where panels would be installed.
The survey combined aerial LiDAR and photogrammetry to deliver the full dataset without requiring physical access to the land beneath the power line corridor.
Project Specification Table
Parameter | Detail |
Survey length | Approximately 15 km of overhead power lines |
Voltage | 220 kV and 110 kV transmission lines |
Ground survey area | Agricultural fields for solar panel installation |
Equipment | DJI Matrice 300 RTK with Zenmuse L1 (LiDAR) and Zenmuse P1 (45 MP photogrammetry) |
Point density achieved | Over 300 points per square metre |
Positional accuracy | 5–6 cm in X, Y, and Z axes (RTK positioning with ground control verification) |
Processing software | 3D Survey (point cloud classification and CAD extraction) |
Cost saving vs traditional survey | Over 70% |
Time saving vs traditional survey | Over 80% |
Client sector | Renewable energy / solar farm development |
The Challenge: Surveying 15 km of High-Voltage Power Lines Without Land Access
The ground area where the solar panels would be installed was relatively straightforward to survey, consisting of open agricultural fields, although some were heavily vegetated with unharvested crops.
The power line corridor presented a problem entirely different. For much of the 15 km route, there was no established access to the land beneath the conductors. A traditional ground-based survey would have required Drone Services Ireland to contact and negotiate access agreements with dozens of individual landowners along the corridor. This process alone could have taken months before any survey work began.
Beyond the access issue, the terrain beneath the power lines was uneven, overgrown, and in many areas, hazardous to work in. Sending ground crews to operate beneath 220 kV conductors in dense vegetation with no clear sight lines posed genuine safety risks. The combination of access complexity, safety concerns, and project timeline constraints made a traditional survey approach impractical.
The Solution: Combined Drone LiDAR and Photogrammetry Survey
Drone Services Ireland combined LiDAR and photogrammetry to capture the complete dataset from the air, eliminating the need for ground access. The survey was carried out using the DJI Zenmuse L1 (LiDAR) and Zenmuse P1 (45 MP photogrammetry sensor) on the DJI Matrice 300 RTK with real-time kinematic positioning.
Using aerial LiDAR, Drone Services Ireland achieved point densities exceeding 300 points per square metre across the survey corridor. This is significantly higher than traditional ground-based survey methods and produces more detailed terrain definition, enabling engineers to identify features such as drainage channels, track boundaries, and micro-topography that influence panel layout and cable routing.
During processing, the LiDAR and photogrammetry point clouds were merged and classified using 3D Survey software. Classification separated the data into ground, low vegetation, medium vegetation, high vegetation, power line conductors, and pole structures. This enabled the extraction of individual poles, conductor lines, and connectors, allowing engineers to visualise and measure the clearance beneath the power lines at any point along the 15 km corridor.
One of the significant advantages of 3D Survey is that it enables the operator to select the exact point in the point cloud using photo support from the P1 imagery. This enhances the accuracy of CAD extraction, particularly for thin or difficult-to-define objects within dense vegetation. By classifying the point cloud, specific classes can be hidden, removing vegetation layers to reveal the underlying terrain and infrastructure for clean CAD linework extraction.
Why LiDAR Was Essential for Power Line Capture
The key difference between LiDAR and photogrammetry is penetration. LiDAR pulses pass through gaps in foliage to reach the ground and structures beneath the canopy. Photogrammetry captures only what is visible from above, meaning dense vegetation obscures the terrain and any infrastructure below it.
For power line surveys specifically, conductor cables are often too small in diameter to be reconstructed accurately through photogrammetry alone. Photogrammetry software frequently struggles to reconstruct the thin cables and complex geometry of 220 kV transmission towers. LiDAR does not have this limitation. Each laser pulse returns a precise 3D coordinate regardless of the object’s thickness or colour, making it the only reliable method for capturing individual conductors, earth wires, and connection hardware.
By combining both technologies, Drone Services Ireland captured the best of each: LiDAR for the power line infrastructure, vegetation penetration, and bare-earth terrain model, and photogrammetry for the high-resolution visual record and orthomosaic of the solar farm ground area.
LiDAR point cloud of 110 kV transmission infrastructure showing classified power lines, poles, and CAD extraction for engineering deliverables.
The Results: 70% Cost Reduction and 80% Time Saving
Compared to a traditional ground-based survey using total stations and requiring individual landowner access agreements along the 15 km corridor, Drone Services Ireland reduced the project cost by over 70% and delivered the complete dataset in less than 20% of the time.
Without needing physical access to the land, the combined LiDAR and photogrammetry point clouds captured the position, height, sag, and span of every overhead conductor. The survey achieved positional accuracy of 5–6 cm in the X, Y, and Z axes, verified against ground control points established using RTK positioning.
The aerial approach eliminated the need to negotiate access across dozens of land parcels and removed all personnel from the hazard zone beneath the 220 kV conductors. No ground crews were required to work in dense vegetation, on uneven terrain, or in close proximity to high-voltage infrastructure.
The survey data was delivered to the client’s engineering team for incorporation into the solar farm planning application.
Equipment and Technical Specification
This project was captured using the DJI Matrice 300 RTK, the enterprise drone platform used by Drone Services Ireland for all survey and inspection operations. The LiDAR data were collected with the DJI Zenmuse L1, and the photogrammetry data were collected with the DJI Zenmuse P1 (45 MP full-frame sensor).
Drone Services Ireland has since upgraded its LiDAR payload to the DJI Zenmuse L2. The L2 delivers 240,000 points per second in single-return mode and up to 1.2 million points per second in multi-return mode with five returns per pulse. It achieves horizontal accuracy of 5 cm and vertical accuracy of 4 cm at an altitude of 150 m, and includes an integrated 20 MP RGB camera. This upgrade further improves capture density and accuracy for power line, corridor, and vegetation surveys.
All survey flights use RTK or PPK positioning, with ground control points established on site for independent accuracy verification.
Wider Applications for Combined LiDAR and Photogrammetry Surveys
The combined LiDAR and photogrammetry approach demonstrated in this project can be applied directly to a range of linear infrastructure surveys across Ireland.
Vegetation encroachment assessments for power line operators and local authorities use the same classified point cloud to measure clearance distances between tree canopy and conductors. This data supports maintenance planning, risk assessment, and compliance reporting without requiring ground access along the full route.
Fibre and telecoms network operators use corridor survey data to identify spans at risk of storm damage, assess cable clearances, and plan maintenance programmes without sending crews to every location on foot. The same technique applies to road and rail corridor surveys, where the combination of terrain model and overhead infrastructure capture provides a complete 3D record of the corridor environment.
Drone Services Ireland has delivered corridor surveys for clients, including BusConnects and telecoms infrastructure providers operating across Ireland. The methodology scales from single-span assessments to multi-kilometre programme surveys.
Frequently Asked Questions
Drone LiDAR achieves positional accuracy of 5–6 cm in X, Y, and Z axes when combined with RTK positioning and ground control point verification. This meets or exceeds the accuracy requirements for planning applications, engineering assessments, and utility compliance reporting.
Yes. LiDAR captures individual conductors, earth wires, and connection hardware that photogrammetry often struggles to reconstruct due to their small diameter. The point cloud allows engineers to measure sag, span length, and ground clearance for each conductor independently.
The aerial capture for this 15 km corridor was completed in a fraction of the time a traditional ground survey would have required. Flight time depends on corridor width, point density requirements, and airspace coordination, but a survey of this scale is typically captured within two to three days of site work, with processed deliverables returned within five working days.
Drone surveys significantly reduce the need for individual landowner access agreements. While drone operations must comply with EASA and IAA regulations regarding overflight, the aircraft does not require physical access to the land beneath the corridor. This was a decisive advantage on this project, where ground access would have required negotiation with dozens of landowners along a 15 km route.
Drone Services Ireland processes LiDAR point clouds using 3D Survey software, which enables automatic and manual classification of ground, vegetation layers, structures, and power line components. Classified point clouds are used for CAD extraction, clearance analysis, digital terrain models, and engineering deliverables compatible with AutoCAD, Civil 3D, and other industry-standard platforms.
Yes. The same combined LiDAR and photogrammetry approach applies to fibre optic routes, telecoms networks, road corridors, and rail infrastructure. Drone Services Ireland has delivered corridor surveys for BusConnects and telecoms infrastructure providers across Ireland.
Discuss Your Power Line or Corridor Survey Project
If you are planning a power line survey, corridor assessment, or renewable energy site survey, contact Drone Services Ireland to discuss your requirements. We provide free quotations and can advise on the most effective survey approach for your project.
Call 087 205 2331 or use our contact form to get started.