High spatial resolution coastal Digital Elevation Models (DEMs) are crucial to assess coastal vulnerability and hazards such as beach erosion, sedimentation, or inundation due to storm surges and sea level rise. This paper explores the possibility to use high spatial-resolution Pleiades (pixel size = 0.7 m) stereoscopic satellite imagery to retrieve a DEM on sandy coastline. A 40-km coastal stretch in the Southwest of France was selected as a pilot-site to compare topographic measurements obtained from Pleiades satellite imagery, Real Time Kinematic GPS (RTK-GPS) and airborne Light Detection and Ranging System (LiDAR). The derived 2-m Pleiades DEM shows an overall good agreement with concurrent methods (RTK-GPS and LiDAR; correlation coefficient of 0.9), with a vertical Root Mean Squared Error (RMS error) that ranges from 0.35 to 0.48 m, after absolute coregistration to the LiDAR dataset. The largest errors (RMS error > 0.5 m) occurred in the steep dune faces, particularly at shadowed areas. This work shows that DEMs derived from sub-meter satellite imagery capture local morphological features (e.g., berm or dune shape) on a sandy beach, over a large spatial domain.

Alves, B., Benavente, J., Ferreira, Ó., 2014. Beach users' profile, perceptions and willingness to pay in Cadiz (SW Spain). In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 521–526, ISSN 0749-0208. Beaches are complex systems on which different activities and interests are pursued. The most widespread activities relate to tourism and recreation. An individual's choice for a particular coast depends on the site characteristics and user's perception. In order to identify beach users' profiles and perceptions, a beach survey was carried out in the beaches of Cadiz, SW Spain, and subsequent sociodemographic factors affecting people's willingness to pay for beach management were identified. Despite part of the economic interests in Cadiz being related to tourism-related activities, most of the beach users are Cadiz residents. Respondents say that the elevated number of people in th...