*2.3. LiDAR Airborne Dataset*

Thanks to multiple LiDAR data acquisition campaigns on the French territory by the French Navy's Hydrographic and Oceanographic Department (SHOM), a LiDAR point cloud was available for the study site. The land/sea continuum is guaranteed by the precision of the topo–bathymetric dataset (horizontal and vertical topographic accuracy of 0.20 m), which was acquired with a Leica HawkEye–3 sensor (Chiroptera + Deep channel).

The 2018 LiDAR point cloud was used to calibrate and validate the digital elevation model (DEM) using 36 validation points that were evenly distributed over the study area. The coordinates in XY (WGS84 UTM 30N) and Z (ellipsoidal height) were extracted for each point (Figure 3).

#### *2.4. Coastal Landscape Classes*

Nine classes that are representative of the coastal landscape were identified (Table 2, Figure 4): dune (white dune vegetation *Ammophila arenaria*), salt marsh (salt marsh vegetation composed mainly of Spartina, Salicornia, Suaeda, and *Halimione portulacoides*), rock, urban (building roof), forest (mix of deciduous and coniferous), field (cultivated and uncultivated), beach (wet and dry sand of grain of 0.06 to 2 mm), road (mainly asphalt), and seawater (shallow to deep salt water). A sub–study site was extracted for the classification tests (red rectangle in Figure 3).

**Figure 3.** 2018 LiDAR of Emerald Coast with evenly distributed calibration points (black circle) and validation points (black triangle); the red rectangle corresponds to the sub–study site.

**Figure 4.** Natural–coloured nadiral Pleaide–1 imagery with the calibration/validation class locations.
