Case Study: Barry Island Dock Wall Survey

A survey-grade 3D model of the Barry Island dock wall, captured by drone and delivered to the client the day after flying.

We surveyed the dock wall at Barry Island using a DJI Mavic 3 Enterprise, tied the imagery to 8 ground control points, verified it against 3 independent checkpoints, and reconstructed it as a 3D model accurate to 20 mm. The client used the model to carry out a condition assessment of the dock infrastructure, without putting inspectors on ropes, boats or scaffolding.

The masonry dock wall in the finished 3D model, with individual stones, joints and iron fixings clearly resolved

The challenge

Dock walls are long, tall and exposed to tide, weather and constant marine wear. Spotting cracking, spalling, missing masonry or displacement means seeing every face of the structure in detail, including areas that are hard to reach from land.

Traditional inspection methods such as rope access, boat-based visual checks or scaffolding are slow, costly and carry safety risks. They also produce notes and photos rather than a measurable record. The client needed a complete, accurate and repeatable view of the wall that their engineers could assess from the office.

Our approach

We flew the survey with the DJI Mavic 3 Enterprise, a compact mapping drone with a high-resolution 4/3 CMOS camera and mechanical shutter. It captures sharp, distortion-free imagery that is well suited to photogrammetry, and its small footprint makes it quick to deploy on a working waterfront.

1. Ground control: before flying, our team established 8 ground control points and 3 checkpoints along the dock and surveyed their positions precisely. The ground control points are used to fix the model in position; the checkpoints are held back as an independent test of its accuracy.

2. Capture: we flew planned flight paths to photograph the wall face, coping and surrounding structure with high overlap from multiple angles, so every surface was covered.

3. Alignment: the imagery was aligned to the ground control points, locking the model to real-world coordinates.

4. Verification: we compared the model against the checkpoints, which played no part in the alignment. This independent test confirmed a final accuracy of 20 mm, so the client can rely on measurements taken from the model.

Steel columns, timber framing and wall-mounted brackets captured in one model, where surface corrosion is visible on every member.

Processing and deliverables

Once aligned, the imagery was reconstructed into a detailed, georeferenced 3D model of the dock wall. Because the model is tied to ground control and its accuracy verified against checkpoints, engineers can take measurements directly from it, not just look at it.

The model gave the client:

• a complete visual record of the wall, viewable from any angle

• the ability to locate and measure defects such as cracks, spalling and missing masonry

• an accurate baseline to compare against future surveys and track deterioration over time

Detail at the base of the structure: timber posts, stone pads and masonry, recorded close enough to assess decay and section loss.

The outcome

The client had their data the day after the survey. Our streamlined workflow, from capture and GCP alignment through to reconstruction, meant there was no waiting weeks for results.

The client's engineers used the 3D model to complete their condition assessment of the dock infrastructure remotely. The survey reduced time on site, removed the need for working at height or over water, and left the client with a lasting digital record of the asset that can inform maintenance planning for years to come.

Need a survey of your structure?

Whether it's a dock wall, sea defence, bridge or building facade, we can capture accurate 3D data quickly and safely, and get it to you fast. Get in touch to discuss your project.