USGS Map service: National Shoreline Change - Historic Shorelines by State

There are critical needs for a nationwide compilation of reliable shoreline data. To meet these needs, the USGS has produced a comprehensive database of digital vector shorelines by compiling shoreline positions from pre-existing historical shoreline databases and by generating historical and modern shoreline data. Historical shoreline positions serve as easily understood features that can be used to describe the movement of beaches through time. These data are used to calculate rates of shoreline change for the U.S. Geological Survey's (USGS) National Assessment of Shoreline Change Project.

Each shoreline may represent a compilation of data from one or more sources for one or more dates provided by one or more agencies. Details regarding source are provided in the 'Data Quality Information' section of the individual shoreline metadata report.

To make this shoreline data more accessible to the public and other agencies, the USGS created this web service. This web service was created utilizing ESRI ArcServer. Vector shoreline layers were collected, organized by state, and symbology made consistent among similar data sets. This service meets open geospatial consortium standards.

岸线数据的全国性可靠汇编存在迫切需求。为满足此类需求，美国地质调查局（U.S. Geological Survey, USGS）通过整合现有历史岸线数据库中的岸线位置，并生成历史与现代岸线数据，构建了一套完整的数字矢量岸线数据库。历史岸线位置可作为直观易懂的特征，用于描述海滩随时间的变迁过程。此类数据被用于计算USGS国家岸线变化评估项目的岸线变化速率。

每条岸线的数据可能整合了一个或多个机构提供的、对应一个或多个时间节点的多源数据。关于数据来源的详细信息，可查阅单条岸线元数据报告中的"数据质量信息"章节。

为向公众及其他机构开放岸线数据的访问渠道，USGS搭建了本项网络服务。该服务基于ESRI ArcServer开发。矢量岸线图层已按州进行收集与整理，并确保同类数据集的符号系统统一规范。本服务符合开放地理空间联盟（Open Geospatial Consortium）标准。