NHD Rivers, Streams, Canals, etc

National Hydrologic Dataset downloaded from USGS on 2/4/2022. This data is also available from the USGS as a service at https://hydro.nationalmap.gov/arcgis/rest/services/nhd/MapServer Abstract: 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. Use the metadata link, http://nhdgeo.usgs.gov/metadata/nhd_high.htm, for additional information. Purpose: The NHD is a national framework for assigning reach addresses to water-related entities, such as industrial discharges, drinking water supplies, fish habitat areas, wild and scenic rivers. Reach addresses establish the locations of these entities relative to one another within the NHD surface water drainage network, much like addresses on streets. Once linked to the NHD by their reach addresses, the upstream/downstream relationships of these water-related entities--and any associated information about them--can be analyzed using software tools ranging from spreadsheets to geographic information systems (GIS). GIS can also be used to combine NHD-based network analysis with other data layers, such as soils, land use and population, to help understand and display their respective effects upon one another. Furthermore, because the NHD provides a nationally consistent framework for addressing and analysis, water-related information linked to reach addresses by one organization (national, state, local) can be shared with other organizations and easily integrated into many different types of applications to the benefit of all.本国家水文数据集（National Hydrologic Dataset）于2022年2月4日从美国地质调查局（USGS）下载获取。该数据亦可通过USGS提供的服务接口获取，访问地址为：https://hydro.nationalmap.gov/arcgis/rest/services/nhd/MapServer 摘要：国家水文数据集（下文简称NHD）是一套基于要素的数据库，用于互连并唯一标识构成美国地表排水系统的河道分段或河段。NHD最初以1:100000比例尺开发，并在全美范围内采用该比例尺标准。本高分辨率NHD通常以1:24000/1:12000比例尺开发，为原始1:100000比例尺的NHD补充了详细信息。（阿拉斯加、波多黎各及美属维尔京群岛的相关数据采用高分辨率标准开发，未使用1:100000比例尺。）针对具备合作方与数据资源的区域，当前正在开发适配当地分辨率的NHD产品。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征数据。河段定义同时覆盖各类水体，以及五大湖、大西洋、太平洋与墨西哥湾的近似岸线范围。NHD同时遵循由联邦地理数据委员会制定的国家空间数据基础设施框架标准。如需获取更多信息，请访问元数据链接：http://nhdgeo.usgs.gov/metadata/nhd_high.htm 数据集用途：NHD作为国家级框架，可为各类涉水实体分配河段地址，例如工业排放点、饮用水源地、鱼类栖息地、野生与风景河流等。河段地址可在NHD地表排水网络中确定各涉水实体的相对位置，如同街道地址体系一般。通过河段地址与NHD关联后，即可利用从电子表格到地理信息系统（GIS）等各类软件工具，分析这些涉水实体的上下游关联关系及其附带的各类相关信息。GIS还可将基于NHD的网络分析与土壤、土地利用、人口等其他数据图层相结合，助力理解并可视化展示各类要素间的相互影响机制。此外，由于NHD提供了全国统一的地址分配与分析框架，单个机构（国家级、州级或地方级）通过河段地址关联的涉水信息可与其他机构共享，并可轻松集成至各类不同类型的应用场景中，实现多方共赢。