Cross, VeeAnn A. , 2009, POTO_HSHD: ESRI format Binary Grid of the Hillshade Relief from the Potomac River/Chesapeake Bay Area For Use with USGS Cruise 06018: Open-File Report 2009-1151, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.This is part of the following larger work.Online Links:
- <https://pubs.usgs.gov/of/2009/1151/data/basemap/hillshade/poto_hshd.zip>
- <https://pubs.usgs.gov/of/2009/1151/html/catalog.html>
Cross, VeeAnn A. , Foster, David S. , and Bratton, John F. , 2010, Continuous Resistivity Profiling and Seismic-Reflection Data Collected in 2006 from the Potomac River Estuary, Virginia and Maryland: Open-File Report 2009-1151, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.Online Links:
This is a Raster data set. It contains the following raster data types:
Planar coordinates are encoded using row and column
Abscissae (x-coordinates) are specified to the nearest 30.000000
Ordinates (y-coordinates) are specified to the nearest 30.000000
Planar coordinates are specified in meters
The horizontal datum used is North American Datum of 1983.
The ellipsoid used is Geodetic Reference System 80.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257222.
Sequential unique whole numbers that are automatically generated.
(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)
vatnipp@usgs.gov
The purpose of this dataset is to provide the hillshade grid as a basemap layer for the work in the Potomac River area. The display of this data layer works well when displayed with the elevation/bathymetry grid.
Person who carried out this activity:
(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)
vatnipp@usgs.gov
Data sources produced in this process:
Department of Commerce (DOC), National Oceanic and Atmospheric Adminis, 1998, Chesapeake Bay, VA/MD (M130) Bathymetric Digital Elevation Model (30 meter resolution) Derived From Source Hydrographic Survey Soundings Collected by NOAA: NOAA's Ocean Service, Special Projects (SP), Silver Spring, MD.Online Links:
U.S. Geological Survey (USGS), EROS Data Center, 1999, National Elevation Dataset: U.S. Geological Survey, Sioux Falls, SD.Online Links:
This grid is a combination of two dataset that provide the best-available data for the land elevations and the bathymetry of Chesapeake Bay. The 7.5-minute elevation data for the conterminous United States are the primary initial source data for the land elevation and were acquired from the National Elevation Dataset (NED). The bathymetry dataset was acquired from the NOAA estuarine bathymetry website. This dataset was derived from two hundred ninety-seven surveys dating from 1850 to 1993. The NED website does not specify any value for horizontal accuracy. According to the metadata accompanying the bathymetry dataset, the horizontal accuracy is expressed as an estimated root mean square error (RMSE). The estimate of the RMSE is based upon horizontal accuracy tests of the source soundings used to generate the DEM. As a first approximation the locational accuracy of the source soundings are 0.0015 m at source "Smooth Sheet" scale (120 m @ 1:80,000 to 15 m @ 1:10,000). Smooth Sheets are maps generated as a principle product of each (historic) hydrographic survey with fully corrected soundings plotted on them. In both cases the user needs to refer to the original datasets to establish the details of the data and their estimates of accuracy.
The metadata accompanying the NED dataset does not specify a vertical accuracy. However, the website indicates the vertical accuracy of the National Elevation Dataset (NED) varies spatially because of the variable quality of the source digital elevation models (DEMs). As such, the NED inherits the accuracy of the source DEMs. The most recently published figure of overall absolute vertical accuracy expressed as the root mean square error (RMSE) is 2.44 meters. The estuarine bathymetry metadata indicates the vertical RMSE statistic is used to describe the vertical accuracy of a DEM. It encompasses both random and systematic errors introduced during production of the data. The RMSE is encoded in element number 5 of record C of the DEM. This accuracy estimate includes components related to quantization of the source soundings (1.3 to 0.15 m), the systematic editing of the source data (1percentor 0.10m), un-sampled bathymetric features (estimated at less than 5percentof depth), time related changes (erosion, deposition, and seismic shifts), and dredging operations (cut and fill). It is estimated that the accuracy of the Bathymetric DEMs is 2 percent of depth or 1 meter for depths grater than 20 meters and 2 percentof depth or 0.20 meters for depths shallower than 20 meters. THESE DEMs SHOULD NOT BE USED FOR NAVIGATION. The two datasets used to create this merged product are referenced to different vertical datums. The NED data use a vertical datum of NAVD88 while the estuarine data simply specifies the vertical datum as referenced to the local tidal datum at the time of the hydrographic survey. No adjustment was made to the individual datasets to attempt to eliminate this discrepancy. The user needs to refer to the original datasets to establish the details of the data and their estimates of accuracy.
This dataset represents the complete hillshade-relief grid for the area of interest.
The whole dataset was handled in the same manner.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None.
- Use_Constraints:
- The public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey and the National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) as the originators of the individual datasets. These data are not to be used for navigation.
(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)
vatnipp@usgs.gov
Downloadable Data
Neither the U.S. government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
| Data format: | The WinZip file contains the elements for the ESRI binary grid (the grid folder and the info folder) as well as FGDC compliant metadata. in format WinZip (version 9.0) Size: 13.073 |
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| Media you can order: |
DVD
(Density 4.5
GBytes)
(format UDF)
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The user must be capable of uncompressing the WinZip file. Once uncompressed, the user must have software capable of reading an ESRI binary grid.
(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)
vatnipp@usgs.gov
