The current data model is the National Hydrography Dataset (NHD) Model V2.3.1. Benefits of adopting this part of the standard also include the long-term improvement of the geospatial hydrography data through the establishment of Web data services for hydrography data and maps within the community.Ģ) The NHD is an implementation of this standard, and is defined through a data model. That, in turn, discourages duplicative data collection. It also seeks to decrease the costs and simplify the exchange of hydrography data among local, Tribal, State, and Federal users and producers. The primary purpose of this part of the document is to support the exchange of surface water (hydrography) data, seeking to establish a common baseline for the semantic content of hydrography databases for public agencies and private enterprises. The National Hydrography Dataset (NHD) standards are composed of a three primary references:ġ) The Geographic Information Framework Data Content Standard, Part 6: Hydrography (FGDC-STD-014.6-2008) provides a conceptual framework for hydrography, but does not specifically define the NHD. Legacy Products National Hydrography Dataset The USGS has published the Elevation-Derived Hydrography Data Acquisition Specifications and the Representation Extraction Attribution and Delineation Rules as guidance for delineating elevation-derived hydrographic features for the NHD. Elevation-derived HydrographyĮlevation-Derived Hydrography is hydrography derived directly from elevation data, providing the best possible horizontal and vertical fit between they hydrography and the elevation data it was derived from. Please visit this website for more information about the 3DHP. This specification provides definitions and technical details of feature attributes. 3D Hydrography Program (3DHP) products contains derived water features based on elevation data, non-elevation derived data from cooperators, and data from the National Hydrography Dataset (NHD).
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