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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.

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Distribution Formats
  • ESRI Arc ASCII (Version: 1)
    • File Compression: WINZIP
Distributor DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Point of Contact DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
dem.info@noaa.gov
General Documentation
Associated Resources
  • NTHMP DEM Project
  • Digital Elevation Model of Unalaska, Alaska: Procedures, Data Sources, and Analysis
Originator
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Originator
  • National Tsunami Hazard Mitigation Program (NTHMP)
Publisher
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
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.
Time Period: 1934-01-01  to  2012-08-01
Spatial Reference System: urn:ogc:def:crs:EPSG::4326 MHHW
Spatial Bounding Box Coordinates:
N: 53.95
S: 53.80
E: -166.42
W: -166.66
Spatial Coverage Map:
Themes
  • 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
  • Earth Science > Oceans > Coastal Processes > Coastal Elevation
  • DEM > Digital Elevation Model
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
  • WDC/MGG, BOULDER > World Data Center for Marine Geology and Geophysics, Boulder
  • V: < 1 meter
  • Coastal Relief
  • Gridded elevations
  • Integrated bathymetry and topography
  • 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 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
Places
  • Continent > North America > United States of America > Alaska
  • Ocean > Pacific Ocean > North Pacific Ocean
  • Ocean > Pacific Ocean > North Pacific Ocean > Aleutian Islands
  • Vertical Location > Land Surface
  • Vertical Location > Sea Floor
  • Unalaska
  • Iliuliuk Bay
  • Dutch Harbor
  • Aleutian Islands
Use Constraints No constraint information available
Fees Fee information not available.
Source Datasets
  • NOS Hydrographic Surveys
  • Shuttle Radar Topography Mission (SRTM)
  • Electronic Navigational Charts
  • U.S. Army Corps of Engineers (USACE)
    • Description of Source: hydrographic condition survey of harbor
    • Temporal extent used:  unknown  to 
  • NGDC Multibeam Surveys
  • 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
Lineage Statement Lineage statement not available.
Processor
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Processing Steps
  • 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.
  • Datasets were visually inspected with ArcGIS for identification and editing of data anomalies. Datasets were then compared with overlapping datasets to ensure data consistency.
  • 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.
  • 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

Metadata Last Modified: 2014-10-29

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