National Geophysical Data Center (NGDC), NOAA Satellite and Information Service

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NOAA VDatum DEM Project

NOAA's National Geophysical Data Center (NGDC) is building high-resolution digital elevation models (DEMs) for select U.S. coastal regions in the Gulf of Mexico. These integrated bathymetric-topographic DEMs were developed for NOAA Coast Survey Development Laboratory (CSDL) through the American Recovery and Reinvestment Act (ARRA) of 2009 to evaluate the utility of the Vertical Datum Transformation tool (VDatum), developed jointly by NOAA's Office of Coast Survey (OCS), National Geodetic Survey (NGS), and Center for Operational Oceanographic Products and Services (CO-OPS). Bathymetric, topographic, and shoreline data used in DEM compilation are obtained from various sources, including NGDC, the U.S. Coastal Services Center (CSC), the U.S. Office of Coast Survey (OCS), the U.S. Army Corps of Engineers (USACE), and other federal, state, and local government agencies, academic institutions, and private companies. DEMs are referenced to the vertical tidal datum of North American Vertical Datum of 1988 (NAVD 88) or Mean High Water (MHW) and horizontal datum of North American Datum of 1983 (NAD 83). Cell size ranges from 1/3 arc-second (~10 meters) to 1 arc-second (~30 meters).

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    Distribution Formats
    • ESRI Arc ASCII  (Version: 1)
      • File Compression: WINZIP
    • netCDF  (Version: 1)
      • File Compression: WINZIP
    Distributor Distributor information not available
    No point of contact available for this dataset
    General Documentation
    • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce (comp)
    • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
    • publication: 2009-12-01
    Dataset Progress Status Under development
    Data Update Frequency: As needed
    Purpose: Developed for the Office of Coast Survey (OCS), NOAA Coast Survey Development Laboratory (CSDL) in support of NOAA's Vertical Datum Transformation tool (VDatum).
    Time Period: 2009-01-01  to  Present
    Spatial Bounding Box Coordinates:
    N: 31.25
    S: 28.50
    E: -85.00
    W: -90.75
    Spatial Coverage Map:
    • Earth Science > Oceans > Bathymetry/Seafloor Topography > Seafloor Topography
    • Earth Science > Oceans > Bathymetry/Seafloor Topography > Bathymetry
    • Earth Science > Oceans > Bathymetry/Seafloor Topography > Water Depth
    • Earth Science > Land Surface > Topography > Terrain Elevation
    • Earth Science > Land Surface > Topography > Topographical Relief Maps
    • Earth Science > Oceans > Coastal Processes > Coastal Elevation
    • DEM > Digital Elevation Model
    • H: 1 meter - < 30 meters
    • V: < 1 meter
    • Coastal Relief
    • Gridded elevations
    • Integrated bathymetry and topography
    • Continent > North America > United States of America
    • Ocean > Atlantic Ocean > North Atlantic Ocean
    • Ocean > Atlantic Ocean > North Atlantic Ocean > Gulf of Mexico
    • Vertical Location > Land Surface
    • Vertical Location > Sea Floor
    Use Constraints No constraint information available
    • None
    Lineage Statement Lineage statement not available.
    Processing Steps
    • All datasets obtained by NGDC are converted to common horizontal and vertical datums of NAD 83 geographic and NAVD 88, respectively, using FME and VDatum transformation tool. They are also converted to common file format, ESRI point shapefiles, for visualization and inspection.
    • Datasets are visually inspected with ArcGIS for identification and editing of data anomalies. Datasets are then compared with overlapping datasets to ensure data consistency.
    • xyz files of the bathymetric data are surfaced using GMT's 'surface' tool onto a 1 arc-second grid that is interpolated to fill empty cells. Points extracted every 10 meters along the coastline are also included to ensure that the bathymetric grid reaches zero at the coast. The resulting Arc ASCII grid is imported into ArcGIS and clipped to the coastline to remove values over land.
    • xyz files for each input dataset are gridded using MB-System's 'mbgrid' tool, which utilizes a high-tension spline interpolation method to fill grid cells with no input elevation values. Preferential weighting is given to more recent, higher-accuracy datasets. Gridding is typically performed in quadrants, each with a 5% data buffer. The grids are imported in ArcGIS and seamlessly merged to create an NAVD 88 DEM.
    • The DEMs are quantitatively evaluated by comparing with source datasets and with elevation values extracted from NGS geodetic monuments. They are visually evaluated by converting to UTM-zone coordinates (units of meters horizontally and vertically) and then creating a slope grid to identify gridding artifacts in the DEMs.
    • NOAA's VDatum transformation tool is used to derive an NAVD 88-to-MHW conversion grid. This grid is then added to the NAVD 88 DEM to create a MHW DEM.
    Processing Environment Native Dataset Environment: ESRI ArcCatalog

    Metadata Last Modified: 2015-09-03

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