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The dataset primarily maps features a 1:24,000-scale, but in certain areas provides detail at 1:5,000-scale. A version of the NHD called the NHDPlus is integrated with elevation and other landscape data to create detailed drainage catchments and flow volume and velocity estimates for streams and rivers of the U.S. at 1:100,000-scale.
The National Map is a significant contribution to the U.S. National Spatial Data Infrastructure (NSDI) from the Federal Geographic Data Committee (FGDC) and currently is being transformed to better serve the geospatial community by providing high quality, integrated geospatial data and improved products and services including new generation ...
The USGS Gap Analysis Program maintains four primary data sets: land cover, protected areas, species and aquatic. The GAP Land Cover Data Set is the most complete map ever produced of vegetative associations for the US. Classified into 551 ecological systems, and 32 modified ecological systems (where human impacts have had an effect).
3D rendering of a hydrologically-conditioned digital elevation model. This example from the U.S. Geological Survey shows “walling” or “fencing” using data from the Watershed Boundary Dataset (WBD) and “burning” of streams from the National Hydrography Dataset (NHDPlus).
The United States Geological Survey ((USGS)) is a publicly available source of remotely sensed hydrological data. Historical and real-time streamflow data are also available via the internet from sources such as the National Weather Service (NWS) and the United States Environmental Protection Agency (EPA). A benefit of using GIS softwares for ...
The term hydrography is used synonymously to describe maritime cartography, which in the final stages of the hydrographic process uses the raw data collected through hydrographic survey into information usable by the end user. Hydrography is collected under rules which vary depending on the acceptance authority.
A main product of the VORF project was the gridded vertical correction files which deliver the capability to transfer heights and depths from one vertical reference system to another, "allowing the direct use of depth data from surveys which is referred to a WGS84 compatible datum rather than Chart Datum and thus enabling Hydrographic surveyors to survey without the need to measure tides".
Demo map showing high-resolution SWBD coastlines. The SRTM Water Body Data (SWBD) is a geographical dataset (2003) encoding high-resolution worldwide coastline outlines in a vector format, published by NASA and designed for use in geographic information systems and mapping applications.