NCEI (formerly NGDC)
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Unalaska, Alaska Coastal Digital Elevation Model

browse graphicPerspective view of DEM
NOAA's National Geophysical Data Center (NGDC) is building high-resolution digital elevation models (DEMs) to support individual coastal States as part of the National Tsunami Hazard Mitigation Program's (NTHMP) efforts to improve community preparedness and hazard mitigation. These integrated bathymetric-topographic DEMs are used to support tsunami and coastal inundation mapping. 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 various vertical and horizontal datums depending on the specific modeling requirements of each State. For specific datum information on each DEM, refer to the appropriate DEM documentation. Cell sizes also vary depending on the specification required by modelers in each State, but typically range from 8/15 arc-second (~16 meters) to 8 arc-seconds (~240 meters).
Cite this dataset when used as a source.
  • ID not available.
Search Data
  • DEM text search (search)
    Text search for locating completed and planned DEMs.
  • Bathymetric Data Viewer (search)
    The Bathymetric Data Viewer is an interactive map providing discovery, descriptions, and download capability for bathymetric survey data and digital elevation models archived at NOAA's National Centers for Environmental Information (NCEI).
Download Data
Distribution Formats
  • ESRI Arc ASCII (Version: 1)
    • File Specification: ASCII text version of ESRI ArcGIS raster format
    • File Compression: WINZIP
  • netCDF (Version: 4 Classic)
Distributor DEM Information
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
dem.info@noaa.gov
Dataset Point of Contact DEM Information
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
dem.info@noaa.gov
Time Period: 1934-01-01 to 2012-08-01
Spatial Reference System: urn:ogc:def:crs:EPSG::4326MHHW
Spatial Bounding Box Coordinates:
N: 53.95
S: 53.80
E: -166.42
W: -166.66
Dataset Information
General Documentation
Associated Resources
  • NTHMP DEM Project
    • Bathymetric Data Viewer (search)
      The Bathymetric Data Viewer is an interactive map providing discovery, descriptions, and download capability for bathymetric survey data and digital elevation models archived at NOAA's National Centers for Environmental Information (NCEI).
  • Digital Elevation Model of Unalaska, Alaska: Procedures, Data Sources, and Analysis
Date(s)
  • publication: 2012-10-16
Edition: First
Data Presentation Form: mapDigital
Dataset Progress Status Complete
Data Update Frequency: As needed
Purpose: Developed for the University of Alaska at Fairbanks (UAF), Geophysical Institute for tsunami and coastal inundation modeling efforts for the State of Alaska.
Use Limitations
  • Not to be used for navigation. Although these data are of high quality and useful for planning and modeling purposes, they are not suitable for navigation. For navigation, please refer to the NOS nautical chart series.
  • Produced by the NOAA National Geophysical Data Center. Not subject to copyright protection within the United States.
  • While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
Originator(s)
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
  • National Tsunami Hazard Mitigation Program (NTHMP)
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
Global Change Master Directory (GCMD) Service Keywords
  • DATA ANALYSIS AND VISUALIZATION > GEOGRAPHIC INFORMATION SYSTEMS > WEB-BASED GEOGRAPHIC INFORMATION SYSTEMS
  • DATA MANAGEMENT/DATA HANDLING > DATA SEARCH AND RETRIEVAL
  • DATA ANALYSIS AND VISUALIZATION > VISUALIZATION/IMAGE PROCESSING
Global Change Master Directory (GCMD) Service Keywords
  • DATA ANALYSIS AND VISUALIZATION > GEOGRAPHIC INFORMATION SYSTEMS > WEB-BASED GEOGRAPHIC INFORMATION SYSTEMS
  • DATA MANAGEMENT/DATA HANDLING > DATA SEARCH AND RETRIEVAL
  • DATA ANALYSIS AND VISUALIZATION > VISUALIZATION/IMAGE PROCESSING
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
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 > North Pacific Ocean
  • Vertical Location > Land Surface
  • Vertical Location > Sea Floor
Uncontrolled
  • Unalaska
  • Iliuliuk Bay
  • Dutch Harbor
  • Aleutian Islands
Data Resolution keywords Global Change Master Directory (GCMD) Vertical Data Resolution Keywords
  • < 1 meter
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
    • 2012-06-26T00:00:00 - All datasets obtained by NGDC were converted to common horizontal and vertical datums of WGS84 geographic and Mean Higher High Water, respectively, using FME. They were also converted to common file format, ESRI point shapefiles, for visualization and inspection.
    • 2012-07-03T00:00:00 - Datasets were visually inspected with ArcGIS for identification and editing of data anomalies. Datasets were then compared with overlapping datasets to ensure data consistency.
    • 2012-07-26T00:00:00 - 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 5 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.
    • 2012-08-02T00:00:00 - 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.
    Processing Environment Native Dataset Environment: Microsoft Windows 2000 Version 5.2 (Build 3790) Service Pack 2; ESRI ArcCatalog 9.2.4.1420
    Source Datasets
    • 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: Retrieved processed NOS survey data from archive
    • 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
    • Electronic Navigational Charts
      • OCS Electronic Navigational Charts (download)
        Digital database of NOAA nautical chart information.
      • Description of Source: bathymetric sounding data
      • Temporal extent used: Unknown to
    • U.S. Army Corps of Engineers (USACE)
      • Description of Source: hydrographic condition survey of harbor
      • Temporal extent used: Unknown to
    • NGDC Multibeam Surveys
      • NGDC Multibeam Survey Database (download)
        Digital database of NGDC multibeam surveys.
      • Description of Source: Multibeam swath sonar surveys
      • Temporal extent used: 2002-01-01 to 2010-01-01
    • UAF Unalaska GPS
      • Description of Source: GPS survey data obtained from UAF
      • Temporal extent used: Unknown to
    • Unalaska Topographic Contours
      • Description of Source: Topographic contour vector data
      • Temporal extent used: Unknown to
    • Bench Mark Data Sheet with Tidal Datum References
      • Tides and Currents Station Selection
        Bench Mark Data Sheet for station 9462620
      • Description of Source: tidal information table from which vertical datum adjustment information are interpreted
      • Temporal extent used: 1997-01-01 to 2001-01-01
    Acquisition Information (collection)
    Instrument
      Platform
      • Digital Elevation Model
      Operation
      • NTHMP DEM Gridding Project
      Last Modified: 2017-09-01
      For questions about the information on this page, please email: dem.info@noaa.gov