NHD Subset of Blueline Streams in Kentucky

A subset of the USGS National Hydro Dataset (NHD) containing only blueline streams. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the stream segments or reaches that make up the nation's surface water drainage system. NHD data was originally developed at 1:100,000-scale and exists at that scale for the whole country. This high-resolution NHD, generally developed at 1:24,000/1:12,000 scale, adds detail to the original 1:100,000-scale NHD. (Data for Alaska, Puerto Rico and the Virgin Islands was developed at high-resolution, not 1:100,000 scale.) Local resolution NHD is being developed where partners and data exist. The NHD contains reach codes for networked features, flow direction, names, and centerline representations for areal water bodies. Reaches are also defined on waterbodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee.本数据集为美国地质调查局（United States Geological Survey, USGS）国家水文数据集（National Hydro Dataset, NHD）的子集，仅包含蓝线溪流（blueline streams）。国家水文数据集（National Hydrography Dataset, NHD）是一套基于要素的数据库，用于关联并唯一标识构成美国地表排水系统的河流段与河段。NHD数据最初以1:10万比例尺开发，全美范围内均采用该比例尺的数据。本高分辨率版本的NHD通常以1:24000/1:12000比例尺开发，为原始1:10万比例尺的NHD补充了细节信息。（阿拉斯加、波多黎各和美属维尔京群岛的数据采用高分辨率格式开发，未采用1:10万比例尺。）在具备合作主体与数据资源的区域，本地化分辨率版本的NHD目前正在开发中。NHD包含网络化要素的河段编码、流向、名称，以及面状水体的中心线表达形式。河段的定义范围还涵盖各类水体，以及五大湖、大西洋、太平洋与墨西哥湾的近似岸线。NHD同时遵循由联邦地理数据委员会（Federal Geographic Data Committee, FGDC）制定的国家空间数据基础设施框架标准。