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SWWA26_500UTM: Southwest Washington 500 meter, 1926 Bathymetry Grid; UTM Projection

Metadata also available as - [Outline] - [Parseable text] - [DIF]

Frequently-anticipated questions:

What does this data set describe?

Title:
SWWA26_500UTM: Southwest Washington 500 meter, 1926 Bathymetry Grid; UTM Projection
Abstract:
SWWA26_500UTM is a digital bathymetric surface grid of the seafloor off the coast of Southwest Washington and Northwest Oregon. Grid cell spacing is 500m and the projection is UTM, Zone 10. The surface was produced by gridding National Ocean Service (NOS) Hydrographic Surveys collected between 1926 and 1928. This work includes the most recent bathymetric data available on a regional scale over the inner to middle continental shelf off the coast of Washington. The results represent the best available estimate of the seafloor morphology for the time period circa 1926.
Supplemental_Information:
The SWCES was initiated to examine coastal geology, processes, and natural hazards within the Columbia River littoral cell. The study is jointly directed by the U.S. Geological Survey Coastal and Marine Geology Program and the Washington State Department of Ecology Shorelands and Environmental Assistance Program, with active participation of local communities in Pacific and Grays Harbor counties. Related USGS work in the Southwest Washington Coastal Erosion Study can be found online at: <http://www.ecy.wa.gov/programs/sea/swce/>
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 1928. Most data were collected between 1926 and 1927. Refer to Gibbs and others, 2000 for details.
  1. How should this data set be cited?

    Gibbs, Ann E., 2000, SWWA26_500UTM: Southwest Washington 500 meter, 1926 Bathymetry Grid; UTM Projection: U.S. Geological Survey (USGS), Menlo Park, CA.

    This is part of the following larger work.

    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.: U.S. Geological Survey Open-File Report 00-448.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -124.55891725
    East_Bounding_Coordinate: -123.91819534
    North_Bounding_Coordinate: 47.35233047
    South_Bounding_Coordinate: 45.87474294

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 1926
    Ending_Date: 1928
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: raster digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      • Dimensions 327 x 93, type Grid Cell

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 10
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -123.
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 500
      Ordinates (y-coordinates) are specified to the nearest 500
      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.

      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Mean lower low water
      Depth_Resolution: 1.0
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    This Program is jointly funded by the Washington State Department of Ecology and the US Geological Survey, Coastal & Marine Geology Program.

  3. To whom should users address questions about the data?

    United States Geological Survey (USGS), Coastal and Marine Geology (CMG)
    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

Why was the data set created?

This bathymetric surface grid is intended for use as an historical 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.

How was the data set created?

  1. From what previous works were the data drawn?

    NOS_HSD (source 1 of 2)
    National Geophysical Data Center, 1998, National Ocean Service Hydrographic Survey Data: US Coastal Waters. CD-ROM Set, Version 4.0.: NOAA Data Announcement 98-MGG-03, World Data Center for Marine Geology & Geophysics, Boulder CO.

    Type_of_Source_Media: CD-ROM
    Source_Contribution: All pre-1998 hydrographic data were obtained from this source.

    SWWA26PTS_UTM (source 2 of 2)
    US Geological Survey, CMG, 2000, Point coverage SWWA26PTS_UTM.

    Type_of_Source_Media: online
    Source_Contribution: Edited NOS hydrographic data points used for gridding.

  2. How were the data generated, processed, and modified?

    Date: 1999 (process 1 of 2)
    Data were processed using both ARC/INFO (v. 7.1) and SURFER32 (v 6.0). Original NOS point data were projected from geographic units (latitude/longitude, datum NAD27) to the Washington State Plane South coordinate system (datum NAD83). Non-sounding data (cartographic code not equal to 711; rocks awash, pilings, etc.) and obviously erroneous or questionable data (based on contour *donuts*, trackline crossing inconsistencies, etc.) were edited out of the data set. USACE data for Grays Harbor and Willapa Bay were converted from Washington State Plane South (feet) and for the Columbia River from Oregon State Plane (feet). SURFER was used to generate preliminary grids of all the data. Data editing and final grid construction was completed using ARC/INFO.
    Individual grids were processed using different data sets and gridding methodologies. Grid boundaries for the SWWA and ORWA grids are listed in Tables 3 and 4, respectively.
    The SWWA26 grid was created by gridding three subsets of edited NOS point data (midshore; nearshore; shoreface; Fig. 2) using parameters that best fit the individual data set. Subset boundaries were determined based on differences in the original 1926 survey scale, sounding distribution, and data precision (see Gibbs and Gelfenbaum, 1999 for a more detailed description). Each subset was gridded separately in SURFER, using the processing steps outlined in Table 5, then imported into ARC/INFO, clipped to its specific boundary, and merged with the other sub-grids to create the final SWWA26 surface.
    The SWWA98 grid is the SWWA26 grid with a subset of merged and gridded 1926/1998 point data nested within it. The merged 1926/1998 point data set includes both the 1998 USACE hydrographic data from the approaches to and ebb-tidal deltas of Grays Harbor, Willapa Bay, and the Columbia River, and portions of the 1926 NOS hydrographic data set. Because of large changes that have occurred in the location and morphology of these ebb-tidal deltas since 1926, the merged data have, in places, abrupt and irregular boundaries. In order to obtain a smooth transition across the survey boundaries, data was edited, modified, and, where necessary, point data added, based on inferred shoreface and ebb-tidal delta morphology. This modified and merged 1926/1998 data set was then gridded, clipped to the modified 1998 survey boundaries, and mosaicked with SWWA26 to produce the final SWWA98 surface. Specific techniques used to create the merged 1926/1998 point data set are discussed in the following section Generating The Modern 1998 Hydrographic Data Set. Specific grid processing parameters used to create SWWA98 are shown in Table 6.
    The ORWA grids include gridded raw, unedited NOS hydrographic data with the more rigorously edited and processed SWWA grids nested within them. The NOS point data were gridded using a linear kriging algorithm, matrix smoothed, and mosaicked with either the SWWA26 or SWWA98 grid to create the final ORWA26 and ORWA98 surfaces, respectively. Specific processing parameters are shown in Table 7.

    Date: 1999 (process 2 of 2)
    NOS_HDB data projected from Lat/Long NAD27 to WASP South Zone 5626, edited of erroneous points, and converted to UTM10.

  3. What similar or related data should the user be aware of?

    Ann E. Gibbs and Guy Gelfenbaum, 1999, Bathymetric change off the Washington/Oregon Coast: Coastal Sediments '99 Proceedings of the 4th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes.

    Gibbs, A.E., Buijsman, M.C., and Sherwood, C, 2000, Non-navigational Gridded Bathymetry Data : The Washington-Oregon Coast, 1926-1998; A data release and description of methods: U.S. Geological Survey Open-File Report OF 00-448.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    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).

  2. How accurate are the geographic locations?

    Horizontal accuracies for NOS surveys vary by water depth and distance from shore (see Gibbs and Gelfenbaum, 1999).

  3. How accurate are the heights or depths?

    Vertical accuracies for NOS surveys vary by water depth and distance from shore (see Gibbs and Gelfenbaum, 1999).

  4. Where are the gaps in the data? What is missing?

    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.

  5. How consistent are the relationships among the observations, including topology?

    Only NOS sounding data with an original cartographic code of 711 are included. The data set was rigorously edited of obviously erroneous points.

How can someone get a copy of the data set?

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.

  1. Who distributes the data set? (Distributor 1 of 1)

    United States Geological Survey (USGS), Coastal and Marine Geology (CMG)
    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

  2. What's the catalog number I need to order this data set?

    USGS Open-File Report 00-448

  3. What legal disclaimers am I supposed to read?

    Please recognize the US Geological Survey and Southwest Washington Coastal Erosion Study 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.

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 18-Oct-2000
Metadata author:
United States Geological Survey (USGS), Coastal and Marine Geology (CMG)
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

Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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