WA_baseline.shp - Offshore baseline for the Washington coastal region generated to calculate shoreline change rates

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目的地，周边往往分布着坐拥高价值不动产的聚居社区。尽管海岸基础设施频繁面临洪涝与侵蚀威胁，沿海开发活动仍呈上升趋势。由此，社会对精准获取过去与当前海岸线变化相关信息的需求与日俱增。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，正依托《海岸线变化国家评估》项目，对美国本土毗邻沿海区域、阿拉斯加部分区域及夏威夷的远洋沙质海岸沿线现有可靠历史海岸线数据进行汇编。
目前尚未有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法因研究而异，致使无法将各研究结果整合为州级或区域级的综合评估。本国家评估项目的发起初衷，便是开发一套跨海岸统一的标准化岸线位置变化测量方法，以助力以内部统一标准定期、系统地更新评估结果。