The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Download
Publications Copernicus
Download
Citation
Articles | Volume XLIII-B1-2021
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLIII-B1-2021, 51–56, 2021
https://doi.org/10.5194/isprs-archives-XLIII-B1-2021-51-2021
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLIII-B1-2021, 51–56, 2021
https://doi.org/10.5194/isprs-archives-XLIII-B1-2021-51-2021

  28 Jun 2021

28 Jun 2021

EVALUATING DIFFERENT WATER-LAND-BOUNDARY APPROXIMATIONS TO IMPROVE SAR-DERIVED DIGITAL ELEVATION MODELS

B. Schneider1, E. Wortmeyer2, S. Schmitz3,4, A. Thiele3,4, P. Havel1, and H. Dirks2 B. Schneider et al.
  • 1German Federal Institute of Hydrology, Koblenz, Germany
  • 2Lower Saxony Water Management, Coastal Defence and Nature Conservation Agency, Coastal Research Station, Norden, Germany
  • 3Institute of Photogrammetry and Remote Sensing, Karlsruhe Institute of Technology, Karlsruhe, Germany
  • 4Fraunhofer IOSB, Ettlingen, Institute of Optronics, System Technologies and Image Exploitation, Germany

Keywords: SAR, RTK, GNSS, ALS, Water-Land-Boundary, Sea-Level, German Wadden Sea, Tidal Flats

Abstract. The coastline of the German Wadden Sea is constantly subjected to the tides and the tidal-induced environmental changes like erosion and accumulation of sediments need to be monitored constantly. This task requires digital elevation models (DEMs), which are derived from remote sensing data. To model those DEMs, a separation of data collected over landmasses and water bodies is required. In the GeoWAM project the potential of airborne SAR-data (F-SAR) is investigated for monitoring purposes in the Wadden Sea. As part of the project, this paper focuses on the suitability of F-SAR data regarding the derivation of water-land-boundaries (WLBs). Therefore, water-land-boundaries based on independent data sets are compared and evaluated. Analyzed data sets include data collected via F-SAR, airborne laserscanning (ALS), on site GNSS measured WLB points and sea-level data from two acoustic gauges. The algorithms were tested on a study site on Spiekeroog island. Our results show, that the accuracies of the derived WLBs mostly depend on the on-site topography and sediments. The spatial deviation between the reference data and the approximated WLBs is mostly less than 2 m horizontally and 0.15 m vertically. Identified challenges to overcome are mostly related to processing of F-SAR data in areas with highly water saturated sediments. Our results suggest, that F-SAR data in tidal flats is not necessarily dependent on further supplementing surveys, as one of the main advantages of the F-SAR data is the potential to derive DEMs and WLBs from the same data set.