NCEI (formerly NGDC)
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Sand Point, Alaska 1/3 arc-second MHW Coastal Digital Elevation Model

browse graphicArcGIS Hillshade DEM
NOAA's National Geophysical Data Center (NGDC) is building high-resolution digital elevation models (DEMs) for select U.S. coastal regions. These integrated bathymetric-topographic DEMs are used to support tsunami forecasting and modeling efforts at the NOAA Center for Tsunami Research, Pacific Marine Environmental Laboratory (PMEL). The DEMs are part of the tsunami forecast system SIFT (Short-term Inundation Forecasting for Tsunamis) currently being developed by PMEL
for the NOAA Tsunami Warning Centers, and are used in the MOST (Method of Splitting Tsunami) model developed by PMEL to simulate tsunami generation, propagation, and inundation. Bathymetric, topographic, and shoreline data used in DEM compilation are obtained from various sources, including NGDC, the U.S. National Ocean Service (NOS), the U.S. Geological Survey (USGS), the U.S. Army Corps of Engineers (USACE), the Federal Emergency Management Agency (FEMA), and other federal, state, and
local government agencies, academic institutions, and private companies. DEMs are referenced to the vertical tidal datum of Mean High Water (MHW) and horizontal datum of World Geodetic System 1984 (WGS84). Grid spacings for the DEMs range from 1/3 arc-second (~10 meters) to 3 arc-seconds (~90 meters).
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Distribution Formats Format not available
    Distributor Distributor information not available
    Dataset No POCs available for this dataset
    Time Period 1910-01-01 to 2009-01-01
    Spatial Bounding Box Coordinates
    N: 55.7
    S: 54.7
    E: -159.17
    W: -160.9
    Spatial Coverage Map
    General Documentation
    Associated Resources
    Publication Dates
    • publication: 2012-03-26
    Edition First
    Data Presentation Form mapDigital
    Dataset Progress Status
    • Complete
    Data Update Frequency As needed
    Purpose Developed for the Pacific Marine Environmental Laboratory (PMEL), NOAA Center for Tsunami Research program in support of NOAA's tsunami forecasting and warning efforts.
    Originator(s)
    • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
    Publisher(s)
    • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
    Theme keywords Global Change Master Directory (GCMD) Science Keywords
    • 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 > Topographical Relief Maps
    • Earth Science > Oceans > Coastal Processes > Coastal Elevation
    Uncontrolled
    • Coastal Relief
    • Gridded elevations
    • Integrated bathymetry and topography
    Platform keywords Global Change Master Directory (GCMD) Platform Keywords
    • Models/Analyses > DEM > Digital Elevation Model
    Place keywords Global Change Master Directory (GCMD) Location Keywords
    • Ocean > Pacific Ocean > North Pacific Ocean > Gulf of Alaska
    • Vertical Location > Land Surface
    • Vertical Location > Sea Floor
    Uncontrolled
    • Southeast Alaskan Islands
    • Sand Point
    • Sand Point Harbor
    • Alaska
    Data Resolution keywords Global Change Master Directory (GCMD) Horizontal Data Resolution Keywords
    • 1 meter - < 30 meters
    Global Change Master Directory (GCMD) Vertical Data Resolution Keywords
    • < 1 meter
    Keywords
      Keywords
        Use Constraints No constraint information available
        Fees Fee information not available.
        Lineage information for: repository
        Processing Steps
        • 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
        Lineage information for: dataset
        Processor
        • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
        Processing Steps
        • 2012-01-05T00:00:00 - All datasets obtained by NGDC were converted to common horizontal and vertical datums of WGS84 geographic and Mean High Water, respectively, using proj4 and gdal. They were also converted to common file format, ESRI point shapefiles, for visualization and inspection.
        • 2011-05-15T00:00:00 - Datasets were visually inspected with ArcGIS for identification and editing of data anomalies. Datasets were then compared with overlapping datasets to ensure data consistency.
        • 2012-01-16T00:00:00 - xyz files of the bathymetric data were surfaced using GMT's 'surface' tool onto a 1/3 arc-second grid that interpolated to fill empty cells. Points extracted every 10 meters along the coastline were also included to ensure that the bathymetric grid reached zero at the coast. The resulting Arc ASCII grid was imported into ArcGIS and clipped to the coastline to remove values over land.
        • 2012-01-16T00:00:00 - xyz files of the topographic data were surfaced using GMT's 'surface' tool onto a 1/3 arc-second grid that interpolated to fill empty cells. Points extracted every 10 meters along the coastline were also included to ensure that the bathymetric grid reached zero at the coast. The resulting Arc ASCII grid was imported into ArcGIS and clipped to the coastline to remove values over water.
        • 2012-01-17T00:00:00 - xyz files for each input dataset were 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 was given to more recent, higher-accuracy datasets. Gridding was performed in quadrants, each with a 5% data buffer. The grids were imported in ArcGIS and seamlessly merged to create the final DEM.
        • 2012-02-05T00:00:00 - The DEM was quantitatively evaluated by comparing with source datasets and with elevation values extracted from NGS geodetic monuments. It was 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 DEM.
        Source Datasets
        • Electronic Navigational Charts and Raster Nautical Charts
        • NOS Hydrographic Surveys
          • NOS Hydrographic Survey Database (download)
            Digital database of NOS hydrographic surveys that date back to the late 19th century.
          • Description of Source: Source Contribution: hydrographic surveys ; Source Type: online
          • Temporal extent used: 1910-01-01 to 2009-01-01
        Acquisition Information (collection)
        Instrument
          Platform
          • Digital Elevation Model
          Operation
          • Tsunami Inundation Gridding Project
          Last Modified: 2017-12-01
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