A Comparative Study of Shoreline Mapping Techniques

Shorelines are critical information in a Coastal Geographic Information System (CGIS). Shorelines have a dynamic nature. Hence, their definition, mapping, and subsequent utilization are a more complicated issue than people usually think. Different approaches to shoreline mapping are described and analyzed in this paper. In particular, a new method is presented in which tide-coordinated shorelines are derived from periodic satellite observations. A pilot shoreline-mapping project was carried out in the Lake Erie area using NOAA/NGS aerial images and simulated and actual IKONOS images. Several shorelines are generated using different techniques, for instance, by digitizing from aerial orthophotos, intersecting a digital water surface with a coastal terrain model (CTM), and extraction from stereo IKONOS images. In addition, existing shorelines digitized from USGS maps and NOAA T-Sheets are included. All these shorelines are compared, their differences evaluated, and the causes of possible shoreline changes are discussed.