SOCAL1852_1889 - Vectorized Shoreline of Southern California Derived from 1852-1889 Source Data

There are critical needs for a nationwide compilation of reliable shoreline data. To meet these needs, the U.S. Geological Survey (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. Shorelines are compiled by state and generally correspond to one of four time periods: 1800s, 1920s-1930s, 1970s, and 1998-2002. 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 this metadata report. Shoreline vectors derived from historic sources (first three time periods) represent the high water line at the time of the survey, whereas modern shorelines (final time period) represent the mean high water line.针对全国范围内可靠海岸线数据集的整合存在迫切需求。为满足此类需求，美国地质调查局（U.S. Geological Survey, USGS）通过整合既有历史海岸线数据库中的海岸线位置，并生成历史与现代海岸线数据，构建了一套涵盖数字矢量海岸线（digital vector shorelines）的综合数据库。海岸线数据按州进行汇编，且通常对应以下四个时间段之一：19世纪、1920年代-1930年代、1970年代以及1998年-2002年。单条海岸线数据可整合自一个或多个机构提供的一个或多个日期的多源数据。有关数据来源的详细信息，请参见本元数据报告的"数据质量信息（Data Quality Information）"章节。源自历史数据源的海岸线矢量（即前三个时间段的数据集）代表测绘时的高水位线，而现代海岸线（即最后一个时间段的数据集）则代表平均高水位线。