The grid described here is part of a data release of sixteen similar bathymetric grids. These include: 1926 and 1926-1998 merged Oregon/Washington (ORWA) and Southwest Washington study area (SWWA) grids, each at 500m and 750m grid spacing, in UTM Zone 10 (meters) and Washington State Plane South Zone 5626 (meters) projections. The ORWA data set extends from Heceta Head, Oregon to Cape Johnson, Washington, from the shoreline to about 2000m water depth; the SWWA data set extends from Tillamook Head Oregon to Pt. Grenville WA, from the shore to approximately 700m water depth.
The data used to create this bathymetric grid were collected between 1926 and 1998. Most data were collected between 1926 and 1927. Refer to Gibbs and others, 2000 for details.
Gibbs, Ann E., 2000, SWWA98_750SP: Southwest Washington, 750 meter, 1926/1998 Bathymetry Grid; Stateplane Projection: U.S. Geological Survey (USGS), Menlo Park, CA.
This is a Raster data set. It contains the following raster data types:
Planar coordinates are encoded using coordinate pair
Abscissae (x-coordinates) are specified to the nearest 750
Ordinates (y-coordinates) are specified to the nearest 750
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 6378206.4.
The flattening of the ellipsoid used is 1/294.98.
The authors would like to thank Eric Nelson of the Seattle District Army Corps of Engineers for the Grays Harbor and Willapa Bay survey data, and H. Rod Moritz of the Portland District Corps for Columbia River entrance surveys.This Program is jointly funded by the Washington State Department of Ecology and the US Geological Survey, Coastal & Marine Geology Program.
United States Geological Survey (USGS),
c/o Ann E. Gibbs
Geologist
USGS, MailStop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA
(650) 329-5060 (voice)
(650) 329-5190 (FAX)
agibbs@usgs.gov
This bathymetric surface grid is intended for use as a modern bathymetric base map for scientific research. It is not intended for navigational purposes. The grid was originally intended for use in wave modelling experiments as part of the Southwest Washington Coastal Erosion Study (SWCES), a cooperative study by the US Geological Survey and the Washington State Department of Ecology.
National Geophysical Data Center, 1998, National Ocean Service Hydrographic Survey Data: US Coastal Waters. CD-ROM Set, Version 4.0. Data announcement 98-MGG-03. World Data Center for Marine Geology & Geophysics, Boulder CO.
US Army Corps of Engineers; Seattle District, Unpublished material, 1998 Grays Harbor Approach and Conditions Survey.
US Army Corps of Engineers; Seattle District and Waterways Experiment Station, Unpublished material, 1998 Willapa Bay Hydrographic Survey.
US Army Corps of Engineers; Portland District, Unpublished material, 1998 MCR Approach Survey.
US Army Corps of Engineers; Por, CMG, Unpublished material, 1998 MCR Extension survey.
US Geological Survey, CMG, Unpublished material, Point coverage SWWA26PTS_SP.
The data have been thoroughly analyzed for for gross inaccuracies. A discussion of errors and accuracies associated with the original data collection methodologies can be found in Gibbs and Gelfenbaum (1999).
Horizontal accuracies for NOS surveys vary by water depth and distance from shore (see Gibbs and Gelfenbaum, 1999). Modern ACE surveys used DGPS and RTK positioning and have an accuracy of less than one meter.
Vertical accuracies for NOS surveys vary by water depth and distance from shore (see Gibbs and Gelfenbaum, 1999). Modern ACE surveys used single-beam digital fathometers, RTK tides, heave and swell compensator, and have an accuracy of less than one-half meter.
Gaps in the hydrographic survey point data exists west of Willapa Bay from approximately -124.034 to -124.363 degrees longitude and 46.573 to 46.738 degrees latitude and northwest of Tillamook Bay from approximately -123.834 to -124.120 longitude and 45.472 to 45.626 latitude. The remaining data are considered complete.
Only NOS sounding data with an original cartographic code of 711 are included. The data set was rigorously edited of obviously erroneous points.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints:
- Please recognize the U.S. Geological Survey (USGS) as the source of this information.
Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.
This information is not intended for navigational purposes.
Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Feel free to use the data but please cite this publication: Gibbs, A.E., Buijsman, M.C., and Sherwood, C.R., 2000, Non-navigational Gridded Bathymetry Data : The Washington-Oregon Coast, 1926-1998; A data release and description of methods. USGS Open-File-Report OF 00-448.
United States Geological Survey (USGS),
c/o Ann E. Gibbs
Geologist
USGS, MailStop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA
(650) 329-5060 (voice)
(650) 329-5190 (FAX)
agibbs@usgs.gov
Please recognize the US Geological Survey and Southwest Washington Coastal Erosion Study as the source of this informationAlthough these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data.
The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials.
United States Geological Survey (USGS),
c/o Ann E. Gibbs
Geologist
USGS, MailStop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA
(650) 329-5060 (voice)
(650) 329-5190 (FAX)
agibbs@usgs.gov