NZ-BeachTopo30: A National-Scale Beach Topography Dataset for New Zealand Fusing ICESat-2 and Sentinel-2 (30 m)

Description: This dataset (NZ-BeachTopo30) provides a seamless, national-scale beach topography product for New Zealand at a spatial resolution of 30 meters. Please note that the provided file is a fully integrated, mosaicked DEM combining the original DeltaDTM backshore baseline with our newly predicted intertidal elevations. Users do not need to merge the datasets themselves. Key Method: The topography was reconstructed using a machine learning framework (XGBoost) that fuses ICESat-2 laser altimetry control points with Sentinel-2 multispectral time-series features. The model specifically targets and fills the "NoData" voids in the DeltaDTM dataset. Specifications: Region: New Zealand Coastline Resolution: ~1 arc-second Coordinate System: GCS_WGS_1984 (Geographic Coordinate System) Vertical Datum: EGM2008 Time Period: Represents the composite state from 2018–2023. Accuracy: Validated against airborne LiDAR data, the dataset achieves an $R^2$ of 0.75 and an RMSE of 1.19 m.