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

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NTHMP DEM Project

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).

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Distribution Formats
  • netCDF  (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
Documentation links not available.
Originator
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce (comp)
Originator
  • NTHMP > National Tsunami Hazard Mitigation Program
Publisher
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Date(s)
  • publication: 2009-04-20
Dataset Progress Status Under development
Data Update Frequency: As needed
Purpose: Developed for the National Tsunami Hazard Mitigation Program to support tsunami modeling and coastal inundation mapping efforts.
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.
Time Period: 2009-01-01  to  Present
Spatial Bounding Box Coordinates:
N: 62
S: 32
E: -116
W: -180.0
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
  • Ocean > Pacific Ocean > North Pacific Ocean
  • Vertical Location > Land Surface
  • Vertical Location > Sea Floor
Use Constraints No constraint information available
Fees
  • None
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 are converted to common horizontal and vertical datums based on the States' requirements using FME. 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 an 8 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 the final DEM.
  • The DEMs are quantitatively evaluated by comparing with source datasets. 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.
Processing Environment Native Dataset Environment: ESRI ArcCatalog 9.2.4.1420

Metadata Last Modified: 2012-12-21

For questions about the information on this page, please email: kelly.carignan@noaa.gov