Bathymetry from active and passive airborne remote sensing – looking back and ahead

Introduction Knowledge about the bathymetry of water bodies is of high economic, social, and ecologic importance. Whereas charting bathymetry for navigational purposes is indispensable for ensuring safe shipping traffic, monitoring the quantity and quality of fresh water resources gains more and more importance, especially in the light of climate change. In the European context three water related directives, namely the water framework directive (European Union, 2000), the flood directive (European Union, 2007), and the Fauna-Flora-Habitat directive (European Union, 1992), request monitoring in a periodic cycle. Repeat acquisition of rivers and other inland water bodies is one of the essential tasks in fulfilling the above directives and requires efficient techniques for capturing bathymetry. The same applies to the coastal zone with applications in shore protection after storm events, monitoring of benthic habitats, etc.