Using Terrasar-x and Rapideye Data for Change Detection in Wadden Sea Areas

The tidal areas of the oceans are important transition zones between terrestrial and marine ecosystems. In contrast to the non-marine surface of the earth, access to the tidal lands such as the Wadden Sea along the North Sea coast is often difficult. For this reason, remote sensing offers important monitoring tools. In this study, a new change detection approach is presented, adapted to the Wadden Sea and RapidEye satellite data. It is based on a decision tree approach and uses spectral characteristics in combination with GIS Information, neighbourhood connections, textures and shapes of objects. The spectral characteristics are derived from field visits and radiation spectrometer measurements. The extent of the Wadden Sea area is determined by using available GIS Information. For vegetation, the SAVI and different texture measurements are used. Mussel beds are located by neighbourhood analysis and texture. In a first step, the image taken at date one is classified using the decision tree method. For the second image taken at date two the decision tree is extended based on the first classification. After classification of the second scene the detected changes are calculated and displayed. This approach is fully automated: no manual input is necessary for classification and change detection. The method is transferable to other areas and other scenes in the Wadden Sea of Lower Saxony. The results show an accuracy of over 70 per cent.