Shallow Water Bathymetry Derived from Green Wavelength Terrestrial Laser Scanner

Abstract

Shallow water bathymetry has proved to be a challenging task for remote sensing applications. In this work, Green-Wavelength Terrestrial Laser Scanning (GWTLS) is employed to survey nearshore bathymetry under clear atmospheric and water conditions. First, the obtained seabed points were corrected for refraction and then geo-registration, and filtering processes were exerted to obtain an accurate bathymetric surface. Terrain analysis was performed with respect to a reference surface derived from classical surveying techniques. The overall analysis has shown that the best results stem from 35° to 50° incident angles, whereas for angles higher than 65° measurements are not acceptable, although for the same angle in front and close to the instrument accuracy is considered acceptable due to the high laser power. Also, high resolution micro-topography, shallower than 1 m water depth, was managed to be captured. Systematic experimental approaches are expected to improve the GWTLS technique to detect bathymetry, which is anticipated to assist in mapping very shallow foreshore, tidal, and deltaic environments, to contribute conceptual into developing hybrid observation systems for coastal monitoring, and also to be applied in various maritime applications.

Keywords:

• Green-wavelength
• nearshore bathymetry
• terrestrial laser scanner

Acknowledgements

The authors are grateful to P. Gaitanakis for his help during fieldwork and to Dr. Mark Smith (University of Leeds) for providing advices for beam refraction. The two anonymous reviewers, whose comments improved substantially the quality of the manuscript, are gratefully acknowledged.

Additional information

Funding

This research was supported by the BEACHTOUR project (11SYN-8-1466) of the Operational Program ‘Cooperation 2011, Competitiveness and Entrepreneurship’ co-funded by the ERDF and the Greek State.