NHD Waterbody Features in Kentucky

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.

国家水文数据集（National Hydrography Dataset，以下简称NHD）是一款基于要素的数据库，可对构成美国全国地表排水系统的河流段与河段进行互联并赋予唯一标识。NHD数据最初以1:10万比例尺制作，目前全美范围均保有该比例尺的数据集。高分辨率NHD通常以1:2.4万/1:1.2万比例尺制作，可为原始1:10万比例尺的NHD数据补充细节信息。（注：阿拉斯加、波多黎各及美属维尔京群岛的相关数据均采用高分辨率制作，未采用1:10万比例尺。）目前正针对具备合作方与数据支撑的区域开发本地化分辨率的NHD数据。NHD包含网络化要素的河段编码、水流方向、水体名称以及面状水体的中心线表达。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区域。NHD同时遵循由联邦地理数据委员会（Federal Geographic Data Committee）制定的国家空间数据基础设施（National Spatial Data Infrastructure）框架标准。