GEOBIA using very high spatial and temporal resolution radar and optical imagery in tracking water level fluctuations in a freshwater reservoir
Approche orientée objet utilisant la THR spatiale et temporelle pour le suivi du marnage sur les petites retenues continentales françaises
Résumé
Tracking water level fluctuations is important to the study and management of waterbodies. A geographic object-based image analysis using very high spatial and temporal radar interferometry (Cosmo-Skymed and TerraSAR-X) and optical (Pléiades) imagery is adopted in this study for this purpose. A linear regression model was sufficient to correlate the water surface area of a mildly sloping and unencumbered littoral zone spatial subset (extracted from 14 images) to water surface altitude data from the field. Results are excellent (R² = 0.963 and RMSE = 0.42 m for the unsupervised classification, with over 99% of land and water areas well-classified for radar images and 78.91% for optical images) albeit limited by the need for field data and the presence of a mildly sloping and unencumbered littoral zone. Potential solutions to overcome this limitation are briefly discussed.