Using Modern Photogrammetric Techniques to Map Historical Shorelines and Analyze Shoreline Change Rates:Case Study on Bodie Island, North Carolina.

shoreline;aerial photography;GIS;erosion rates

Zink, Jason Michael ; Margery Overton, Committee Chair,Zink, Jason Michael ; Margery Overton ; Committee Chair

University:North Carolina State University

关键词: shoreline;    aerial photography;    GIS;    erosion rates;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/2734/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

The efficacy of coastal development regulations in North Carolina is dependent onaccurately calculated shoreline erosion rates.North Carolina's current methodology for regulatory erosion rate calculation does not take advantage of emerging GIS, photogrammetric, and engineering technologies.Traditionally, historical shoreline positions from a database created in the 1970s have been coupled with a modern shoreline position to calculate erosion rates.The photos from which these historical shorelines come were subject to errors of tilt, variable scale, lens distortion, and relief displacement.Most of these errors could be removed using modern photogrammetric methods.In this study, an effort was made to acquire and rectify, using digital image processing, prints of the original historical photography for Bodie Island, North Carolina.The photography was rectified using the latest available desktop photogrammetry technology.Digitized shorelines were then compared to shorelines of similar date created without the benefit of this modern technology.Uncertainty associated with shoreline positions was documented throughout the process.It was found that the newly created shorelines were significantly different than their counterparts created with analog means.Many factors caused this difference, including: choice of basemaps, number of tie points between photos, quality of ground control points, method of photo correction, and shoreline delineation technique.Using both linear regression and the endpoint method, a number of erosion rates were calculated with the available shorelines.Despite the differences in position of shorelines of the same date, some of the calculated erosion rates were not significantly different.Specifically, the rate found using all available shorelines prior to this study was very similar to the rate found using all shorelines created in this study.As a result of this and other factors, it was concluded that a complete reproduction of North Carolina's historical shoreline database may not be warranted.The new rectification procedure does have obvious value, and should be utilized in those locations where there is no existing historical data, or where existing data is thought to be of poor quality.This would especially be the case near inlets or other historically unpopulated areas.