topo4d: Topographic 4D STAC Extension for Curating and Cataloging Multi-Source Geospatial Time Series Datasets

We developed a new method to automatically detect and group short-term topographic changes on sandy beaches using hourly 3D laser scans collected over three years. By distinguishing variations in patterns of sand deposition and erosion, the approach allows scientists to study how beaches change at different moments in time and link these changes to environmental conditions like winds, waves or bulldozers, improving understanding and prediction of dynamics of sandy beaches.

We mapped the riverbed through a 28 km canyon in southern France using airborne laser measurements, where field surveys are difficult and risky. By reprocessing the full recorded signal and combining it with targeted sonar checks, we recovered deeper and more complete underwater terrain than standard approaches. The resulting riverbed elevation model preserves key channel shapes needed for improved flood simulations, habitat assessment, and river management.

We present a method to extract surface change information from 4D time series of topographic point clouds recorded with a terrestrial laser scanner. The method uses sensor information to spatially and temporally smooth the data, reducing uncertainties. The Kalman filter used for the temporal smoothing also allows us to interpolate over data gaps or extrapolate into the future. Clustering areas where change histories are similar allows us to identify processes that may have the same causes.