Uncertainty table for lidar-derived shorelines used when calculating rates in the Digital Shoreline Analysis System software for Alabama

Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. To meet these national needs, the Coastal and Marine Geology Program of the U.S. Geological Survey (USGS) is compiling existing reliable historical shoreline data along open-ocean sandy shores of the conterminous United States and parts of Alaska and Hawaii under the National Assessment of Shoreline Change project.
There is no widely accepted standard for analyzing shoreline change. Existing shoreline data measurements and rate calculation methods vary from study to study and prevent combining results into state-wide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method of measuring changes in shoreline position that is consistent from coast to coast. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner.

滨海沙质海滩是热门的休闲度假胜地，周边往往坐落着坐拥高价值不动产的社区。尽管海岸基础设施频繁遭受洪涝与侵蚀威胁，沿海开发活动仍呈增长态势。因此，社会对精准掌握过往与当前海岸线变化情况的需求日益攀升。为满足这一国家层面的需求，美国地质调查局（U.S. Geological Survey, USGS）下属的海岸与海洋地质项目组，依托《海岸线变化国家评估（National Assessment of Shoreline Change）》项目，正在汇编美国本土、阿拉斯加部分区域及夏威夷的开阔洋域沙质海岸沿线现有可靠的历史海岸线数据。

目前尚无被广泛认可的海岸线变化分析标准。现有海岸线数据测量方法与岸线变化速率计算方式因研究而异，致使相关结果无法整合至全州或区域尺度的评估工作中。开展本次《海岸线变化国家评估》项目的核心动因，便是研发一套适用于全海岸区域、标准统一的海岸线位置变化测量方法，其目标是便于构建以内部自洽为原则的定期、系统性评估结果更新流程。