NHD Point Features in Kentucky (Legacy)

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）是一套基于要素的数据库，可对构成美国全国地表排水系统的河流河段或区段实现互联，并赋予其唯一标识符。该数据集最初以1:10万比例尺制作，全美范围均采用该比例尺数据。其高分辨率版本通常以1:2.4万/1:1.2万比例尺制作，可为原始1:10万比例尺的数据集补充细节信息。（阿拉斯加、波多黎各及美属维尔京群岛的相关数据直接采用高分辨率制作，未使用1:10万比例尺。）在具备合作方与数据支撑的区域，目前正在开发本地分辨率版本的数据集。该数据集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征数据。河段定义同样适用于各类水体，以及五大湖、大西洋、太平洋与墨西哥湾的近似岸线范围。该数据集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框架标准。