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

browse graphicPerspective view of 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 warning 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 a variety of vertical datums and horizontal datum of World Geodetic System of 1984 (WGS84). Cell size for the DEMs ranges from 1/3 arc-second (~10 meters) to 3 arc-seconds (~90 meters).
Cite this dataset when used as a source.
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    Distributor Distributor information not available
    Dataset No POCs available for this dataset
    Time Period 1915-01-01 to 2010-01-01
    Spatial Bounding Box Coordinates
    N: 59.82
    S: 59.32
    E: -150.89
    W: -152.10
    Spatial Coverage Map
    General Documentation
    Associated Resources
    Publication Dates
    • publication: 2010-12-07
    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
    • 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
    • Continent > North America > United States of America > Alaska
    • Ocean > Pacific Ocean
    • Vertical Location > Land Surface
    • Vertical Location > Sea Floor
    Uncontrolled
    • Kachemak Bay
    • Seldovia
    • Anchor Point
    • Homer
    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: dataset
        Processing Steps
        • 2010-05-03T00:00:00 - All datasets obtained by NGDC were converted to common horizontal and vertical datums of NAD 83 geographic and MHW, respectively. They were also converted to common file format, ESRI point shapefiles, for visualization and inspection.
        • 2010-05-26T00:00:00 - Datasets were visually inspected with ArcGIS for identification and editing of data anomalies. Datasets were then compared with overlapping datasets to ensure data consistency.
        • 2010-10-15T00:00:00 - Coastline dataset was extracted and edited.
        • 2010-10-18T00:00:00 - xyz files of the bathymetric data were surfaced using GMT's 'surface' tool onto 1/3 arc-second grid inside the bay 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.
        • 2010-10-25T00:00:00 - 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.
        • 2010-11-08T00:00:00 - The MHW 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.
        • 2010-11-10T00:00:00 - The MHW DEM was qualitativley evaluated through comparison with nautical charts.
        Processing Environment Native Dataset Environment: Microsoft Windows 2000 Version 5.2 Build 3790 Service Pack 2; ESRI ArcCatalog 9.2.4.1420
        Source Datasets
        • Bench Mark Data Sheets with Tidal Datum References
          • Tides and Currents Station Selection
            Bench Mark Data Sheets
          • Description of Source: Source Contribution: tidal information table from which vertical datum adjustment information are interpreted ; Source Type: online
          • Temporal extent used: 2007-01-01 to 2010-01-01
        • USACE Hydrographic Surveys
          • USACE Alaska District Hydrographic Surveys (download)
            Digital database of hydrographic surveys in Alaska District
          • Description of Source: Source Contribution: Hydrographic surveys for Alaska ; Source Type: online
          • Temporal extent used: Unknown to
        • 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 downloaded from web site. ; Source Type: online
          • Temporal extent used: 1915-01-01 to 2010-01-01
        • Kenai Lidar
          • Kenai Lidar (download)
            ESRI Grid
          • Description of Source: Source Contribution: Lidar dataset acquired via ftp. ; Source Type: online
          • Temporal extent used: 2008-01-01 to 2008-01-01
        • Coastal Kenai Lidar- Hydropalooza
          • Digital Coast Lidar Data Retrieval Tool (download)
            Digital database of lidar surveys
          • Description of Source: Source Contribution: lidar dataset collected and provided by NGS ; Source Type: online
          • Temporal extent used: 2008-01-01 to 2008-01-01
        • Shuttle Radar Topography Mission (SRTM)
          • Shuttle Radar Topography Mission (download)
            global topography
          • Description of Source: Source Contribution: gridded topographic data downloaded from web site. ; Source Type: on web
          • Temporal extent used: Unknown to
        Acquisition Information (collection)
        Instrument
          Platform
          • Digital Elevation Model
          Operation
          • Tsunami Inundation Gridding Project
          Last Modified: 2017-11-27
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