Title:
Sand Point, Alaska Coastal Digital Elevation Model
Abstract:
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 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).
Supplemental information:
1. How should this data set be cited?
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Origin:
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DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
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Pub Date:
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20060929
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Title:
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Sand Point, Alaska Coastal Digital Elevation Model
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Edition:
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First
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Geoform:
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raster digital data
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Sername:
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Issue:
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Pubinfo:
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Boulder, Colorado
DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
User Services
Mailing and Physical Address
NOAA/NESDIS/NGDC E/GC 325 Broadway
Boulder
CO
80305-3328
USA
(303) 497-6826
(303) 497-6513
ngdc.info@noaa.gov
7:30 - 5:00 Mountain
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This is part of the following larger work:
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Origin:
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DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
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Pub Date:
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20060929
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Title:
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Sand Point, Alaska Coastal Digital Elevation Model
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Edition:
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First
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Geoform:
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raster digital data
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Sername:
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Issue:
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Pubinfo:
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Boulder, Colorado
DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
User Services
Mailing and Physical Address
NOAA/NESDIS/NGDC E/GC 325 Broadway
Boulder
CO
80305-3328
USA
(303) 497-6826
(303) 497-6513
ngdc.info@noaa.gov
7:30 - 5:00 Mountain
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2. What geographic area does the data set cover?
Bounding coordinates:
West: -161.00
East: -159.80
North: 55.70
South: 54.70
3. What does it look like?
Description:
Perspective view of DEM
URL:
4. What is the temporal coverage of the data set?
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Begdate:
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1913
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Enddate:
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2006
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5. What is the geospatial form of this data set?
raster digital data
6. How does the data set represent geographic features?
How are geographic features stored in the data set?
As a Raster data set
What is the coordinate system used to represent geographic features?
7. What are the contents of this dataset?
8. What were the instruments or sensors used to collect the data
LIDAR
MSBS
SONAR
9. What satellites, boats or other platforms housed the instruments?
DEM
10. What missions supported the platforms?
Tsunami Inundation Gridding Project
11. What online links are contained in this metadata record?
More Information
Search
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Map Interface
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Graphic geo-spatial search tool for locating completed and planned NOAA tsunami inundation DEMs.
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DEM text search tool
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Text search tool for locating completed and planned NOAA tsunami inundation DEMs.
Download
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Who produced the data set?
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Why was the data set created?
Developed for the Pacific Marine Environmental Laboratory (PMEL), NOAA Center for Tsunami Research program in support of NOAA's tsunami forecasting and warning efforts.
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How was the data set created?
2. What changes have been made?
| Date |
Event |
| 20060801 |
All datasets obtained by NGDC were converted to common horizontal and vertical datums of WGS84 geographic and Mean High Water, respectively, using FME. They were also converted to common file format, ESRI point shapefiles, for visualization and inspection. |
| 20060815 |
Datasets were visually inspected with ArcGIS for identification and editing of data anomalies. Datasets were then compared with overlapping datasets to ensure data consistency. |
| 20060822 |
xyz files of the bathymetric data were surfaced using GMT's 'surface' tool onto a 1 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. |
| 20060831 |
xyz files for each dataset were combined into a single file, which was smoothed using GMT's 'blockmedian' tool to a 3 arc-second grid 5% larger than the final 3 arc-second DEM. GMT's 'surface' tool then applied a tight spline tension to interpolate cells without data values. |
| 20060824 |
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. It was also compared to 1/3 arc-second DEM to ensure elevation consistency. |
3. Who is the person responsible for change?
Barry W. Eakins
DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
NOAA/NESDIS/NGDC
Boulder
Colorado
80305-3328
USA
303-497-6505 (voice)
303-497-6513 (fax)
Barry.Eakins@noaa.gov
Hours of Service:
9am-5pm, M-F, Mountain Time
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How reliable are the data; what problems remain in the data set?
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How well have the observations been checked?
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How accurate are the geographic locations?
The horizontal accuracy of bathymetric and topographic features in the DEM is dependent upon the accuracy of the input datasets used to determine corresponding cell values. Topography: about 100 meters. Positional accuracy of input topographic datasets limits accuracy of corresponding cell values in DEM. USGS NED DEM: 50 to 60 meters. SRTM DEM: 30 meters. Coastal LiDAR surveys: less than 10 meters. Where present, coastal LiDAR data supplant SRTM and NED data values in the DEM. DEM cell-value relative-contribution factors: LiDAR: 100, SRTM: 10, NED: 0.1. Bathymetry: 100 to several hundred meters. Positional accuracy of input bathymetric datasets limits accuracy of corresponding cell values in DEM. NOS multibeam and coastal LiDAR surveys: about 10 meters. Early 20th-century NOS hydrographic soundings are limited by sparseness of deep-water soundings, and potentially large position accuracy of pre-satellite (i.e., GPS) navigation: tens to several tens of meters. Morphologic change in inland rivers and along the coast also degrades the positional accuracy of NOS soundings. Where present, multibeam sonar and coastal LiDAR data supplant older NOS hydrographic sounding data values in the DEM. DEM cell-value relative-contribution factors: NOS LiDAR: 100, multibeam sonar survey data: 100, NOS hydrographic soundings: 1, MEST: 1.
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How accurate are the heights or depths?
The vertical accuracy of bathymetric and topographic features in the DEM is dependent upon the accuracy of the input datasets used to determine corresponding cell values. Topography: 10 to 15 meters. Vertical accuracy of input topographic datasets limits accuracy of corresponding cells in DEM. USGS NED DEM: 7 and 15 meters. SRTM DEM: 16 meters. Where present, coastal LiDAR data supplant SRTM and NED data values in the DEM. DEM cell-value relative-contribution factors: LiDAR: 100, SRTM: 10, NED: 0.1. Bathymetry: 0.3 meters to 5% of water depth. Vertical accuracy of input bathymetric datasets limits accuracy of corresponding cells in DEM. NOS multibeam and coastal LiDAR data: about 0.1 meter. Early 20th-century NOS hydrographic soundings are limited by sparseness of deep-water soundings, and potentially large position accuracy of pre-satellite (i.e., GPS) navigation: several meters. DEM cell relative-contribution factors: NOS LiDAR: 100, NOS multibeam swath sonar bathymetry: 100, NOS hydrographic soundings: 1. Gridding interpolation to determine cell values between sparse NOS hydrographic soundings in deep water degrades the vertical accuracy of deep-water elevations.
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Where are the gaps in the data? What is missing?
NGDC made every effort to obtain all available digital topographic and bathymetric datasets in the region for use in building the DEM.
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How consistent are the relationships among the observations, including topology?
Datasets were visually compared internally and externally (with other overlapping datasets and satellite images and maps) in ESRI ArcGIS for identification of anomalous elevations or data inconsistencies. Where elevation inconsistencies occurred, the most recent and/or highest resolution data set was selected for use in that region. Elevations in the older and/or lower-resolution datasets were deleted prior to building the DEM.
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How can someone get a copy of the data set?
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Who wrote the metadata?
Metadata author:
Barry W. Eakins
DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
NOAA/NESDIS/NGDC
Boulder
Colorado
80305-3328
USA
303-497-6505 (voice)
303-497-6513 (fax)
Barry.Eakins@noaa.gov
Hours of Service:
9am-5pm, M-F, Mountain Time
Date Last Modified
20110829
Metadata Standard
Content Standard for Digital Geospatial Metadata: Extensions for Remote Sensing Metadata
FGDC-STD-012-2002
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MISSION INFORMATION
PLATFORM INFORMATION
INSTRUMENT INFORMATION (General Overview)
1. What instruments were used to collect the data?
Instrument name not available
2. What are the instrument types? (e.g. imager, sounder, magnetometer, gps reciever, etc)
Instrument type not available
3. What are operational modes of the instruments (crosstrack, initialization, solar calibration, etc.)
Operational mode not available
4. How do the instruments collect data? (e.g. whiskbroom, laser, panoramic, etc)?
Collection type not available
5. What are the position and orientation of the instrument components on the platform?
Sensor orientation not available
INSTRUMENT INFORMATION (Sensor Specific)
