Digital Shoreline Analysis System version 4.1 Transects with Short-Term Rate Calculations for the New England North region from Popham Beach, Maine to the northern side of Cape Ann, Massachusetts (NewEnglandN_ST.shp)

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.滨海沙质海滩是广受欢迎的休闲度假胜地，周边往往坐落着坐拥高价值不动产的居民区。尽管沿海基础设施面临洪涝与侵蚀威胁，沿岸开发活动仍呈增长态势。因此，社会对精准掌握海岸历史与当前变迁情况的需求与日俱增。为满足此类国家层面的需求，美国地质调查局（U.S. Geological Survey, USGS）下属的海岸与海洋地质项目，依托“全国海岸线变化评估（National Assessment of Shoreline Change）”项目框架，正在整编美国本土（毗邻美国）、阿拉斯加部分区域及夏威夷的开放海域沙质海岸沿线现有可靠历史海岸线数据。目前尚无被广泛认可的海岸线变化分析标准。现有海岸线数据的测量方式与岸线变迁速率计算方法因研究而异，导致无法将研究结果整合至全州或区域级评估工作中。本全国评估项目的初衷，便是研发一套跨海岸统一的标准化海岸线位置变化测量方法，其目标在于以内部统一的范式，实现海岸变迁评估结果的定期系统化更新，并简化该更新流程。