Accompanying Data for: "Spatial Variability and Drivers of Salt Marsh Cliff Erosion in the Dutch Wadden Sea: from Observation to Simulation"

This repository contains two UAV-derived Digital Elevation Models (DEMs) from the Wierum salt marsh in the Dutch Wadden Sea and a custom Python-based 1D subgrid cliff erosion model. The DEMs were generated from aerial imagery collected using an Atmos Marlyn Cobalt hybrid vertical take-off and landing (VTOL) fixed-wing UAV. The UAV was equipped with a Sony DSC-RX1R II 42-megapixel full-frame RGB camera fitted with a Zeiss Sonnar 35mm lens. Two survey flights were conducted, on 24 November 2022 and 5 September 2023 during low tide, ensuring the mudflat and cliff base were fully exposed. Flights were executed at altitudes between 95 and 105 meters, with an average ground speed of approximately 65 kilometers per hour. To produce the DEMs, structure-from-motion (SfM) photogrammetric processing techniques were applied to the high-resolution imagery. The UAV incorporated Real-Time Kinematic (RTK) and Post-Processed Kinematic (PPK) GNSS corrections, allowing for centimeter-scale positional accuracy. Field-deployed ground control points (GCPs) provided additional geometric control and served as validation for the elevation models. Horizontal and vertical accuracies of the DEMs are approximately 2 cm and 3 cm, respectively. The DEMs are referenced in the coordinate reference system RD New + NAP height (EPSG:7415).