Shoreline extraction using satellite imagery

Shoreline change is considered to be one of the most dynamic processes in the coastal area. It has become important to map shoreline changes as an input data for coastal hazard assessment. In recent years, satellite remote sensing data has been used in shoreline extraction and mapping. The accuracy of image orthorectification, as well as the accuracy of image classification, are the most important factors affecting the accuracy of the extracted shoreline. In this study, the shoreline of the area of Georgioupolis was mapped for the years 1998 and 2005 using aerial imagery and Ikonos data, respectively. Ikonos data were orthorectified and a feature extraction technique was then used to extract the shoreline. This technique employed machine-learning algorithms which exploit both the spectral and spatial information of the image. Results were validated with in situ measurements using Differential GPS. The analysis showed that there have not been severe changes in the shoreline between 1998 and 2005, except in some locations where change was substantial.