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Abstract
The objective of this research is to use geographic information systems (GIS) to quantify shoreline position change during 1954 and 1999 for Sapelo Island and Jekyll Island in Georgia, USA. Shorelines from multiple years were manually traced from digital raster graphics, aerial photographs, digital orthophoto quad quadrangles and a lidar image using ArcView GIS software, Version 3.3. This study showed that the northern ends of Jekyll and Sapelo islands are eroding, whereas the southern ends are accreting. Mann-Whitney test (two-tailed) indicated that the mean accretion rates and annual change rates (regardless of direction) of the two islands differed statistically during 1954-1974,1974-1993 and 1954-1999. The mean recession rates were significantly different during 1954-1974 and 1974-1993, but not so for 1954-1999. Human activity exerted a heavy influence on the shoreline change. Quantifying shoreline change provides useful data on the effects of engineering structures on erosion and is important for coastal zone management and planning.