Hydrographic surveys have been conducted using small boats of the Institut Universitaire Européen de la Mer (https://www.flotteoceanographique.fr/en/Facilities/Vessels-Deep-water-submersible-vehicles-and-Mobile-equipments/Station-vessels/Albert-Lucas), which can be equipped with a range of sensors for data acquisition in the nearshore zone. For each survey, we prepared a Digital Elevation Model (DEM) at a fixed sampling distance of 0.5 m.

DEMs covering both subaerial and subtidal domains were created by fusing topographic and bathymetric DEMs collected concurrently. Fusion DEMs provide an overview of sedimentary bedforms across the air-water interface. Comparison of measured topographic and bathymetric elevations at the overlap provides means for additional data verification.

In order to facilitate capturing three-dimensional beach change, full surveys of the subaerial beach have been conducted starting in 2004 using RTK-GNSS (survey method GPS), Unmanned Aerial Vehicle (UAV) imagery processed using Structure-from-Motion (SfM) photogrammetry (survey method PHO) and terrestrial laser-scanning (survey method TLS). For each survey, we prepared a Digital Elevation Model (DEM) at a fixed sampling distance of 0.5 m.

Digital Elevation Model (DEM) and orthophotography of La Palue and Lostmarc’h beaches in Crozon peninsula derived from the photogrammetric processing of drone images (Mavic 3E RTK) with a flying height of 100 m.

Digital Elevation Model (DEM) and orthophotography of La Palue and Lostmarc’h beaches in Crozon peninsula derived from the photogrammetric processing of drone images (DJI Phantom 4 RTK) with a flying height of 100 m.

Digital Elevation Model (DEM) and orthophotography of La Palue and Lostmarc’h beaches in Crozon peninsula derived from the photogrammetric processing of drone images (DJI Phantom 4 RTK) with a flying height of 100 m.

Digital Elevation Model (DEM) and orthophotography of La Palue and Lostmarc’h beaches in Crozon peninsula (France) from the photogrammetric processing of drone images (DJI Phantom 4 RTK) with a flying height of 100 m.

Digital Elevation Model (DEM) and orthophotography of La Palue and Lostmarc’h beaches in Crozon peninsula derived from the photogrammetric processing of drone images (DJI Phantom 4 RTK) with a flying height of 100 m.

Beach profiling using RTK-GNSS (survey method GPS) represents one of the most convenient method for frequent resurveys. Since 2003, profile surveys have been (approx.) weekly for the first year, fortnightly between January 2004 and June 2005, and near-monthly thereafter, with occasional gaps in the data due to equipment misfunctioning and maintenance. Trimble 5700/5800 and Topcon Hiper V GPS systems were used for data acquisition.

Orthophotos were obtained concurrently with photogrammetric DEMs. They were derived from Unmanned Aerial Vehicle (UAV) imagery processed using Structure-from-Motion photogrammetry (survey method PHO).