ORCID
- Storm Roberts: 0000-0003-3882-1798
- Sarah Boulton: 0000-0002-8251-0025
- Alison Raby: 0000-0002-8959-0080
Document Type
Article
Abstract
Traditional field methods rely on tape measures to record boulder dimensions, whilst modern handheld LiDAR and Structure from Motion photogrammetry approaches are increasingly used to obtain dimensions and volumes with potentially greater accuracy. Although drone-based remote sensing remains underutilised for boulder studies, it shows promise for rapidly collecting large datasets by digitising boulder outlines on orthomosaics of aerial photographs. This study assesses the accuracy of using boulder statistics extracted from digitised perimeters and LiDAR generated 3D models, and tests whether the results are statistically comparable with manually collected field data. These methods were tested on boulder ridges at the Grind o' da Navir, Shetland, Scotland. When compared with traditional field measurements, LiDAR-derived volumes are up to 37% smaller, suggesting that manual methods may systematically overestimate boulder size. When validated on the same boulders, the 2D digitisation method yielded mean differences of just 0.05 m for the A-axis and 0.02 m for the B-axis, with similar histogram distributions to the traditional method. A-axis orientation results also show broadly similar distributions between the two methods, implying the digitised perimeter method can be used to reveal flow directions of the causative storm waves. These findings demonstrate that the boulder digitisation method is suitable for investigating entire deposits of thousands of boulders, quicker than with traditional field methods, with good accuracy at population level.
DOI Link
Publication Date
2026-10-19
Publication Title
Earth Surface Processes and Landforms
Volume
51
Issue
10
ISSN
0197-9337
Acceptance Date
2026-09-29
Deposit Date
2026-10-23
Keywords
Coastal boulder deposit, LiDAR, Methods, Storm waves, UAV
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Roberts, S., Boulton, S., Raby, A., & Manzella, I. (2026) 'A Comparison of Manual vs. Digital Measurement Methods for the Investigation of Coastal Boulder Deposits at the Grind o' da Navir, Shetland', Earth Surface Processes and Landforms, 51(10). Available at: 10.1002/esp.70436
