Grid Representing the Landward DEM and the Present Day Bathymetry of the Columbia River within the SWCES Study Area

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Frequently-anticipated questions:

What does this data set describe?

    Title:
    Grid Representing the Landward DEM and the Present Day Bathymetry of the Columbia River within the SWCES Study Area
    Abstract:
    Two 21-day field operations were conducted in 1997 and 1998 in the estuaries and on the inner continental shelf off the northern Oregon and southern Washington coast. These cruises aboard the R/V Corliss were run in order to generate reconnaissance maps of the seafloor geology and the shallow subsurface stratigraphy using sidescan sonar and seismic-reflection mapping techniques. The 1998 cruise also collected sediment grab samples, bottom photographs, and video images to verify the sidescan-sonar imagery and to document the seafloor geology. The combination of these data with previously collected sediment sample data (Robert, 1974; Nittrouer, 1978; and Smith et. al., 1980) has been used to define the extent and lithology of shelf sediments associated with the Columbia River littoral cell. This work is one component of a larger project studying the erosion of the Washington and Oregon coast and is being coordinated by the U.S. Geological Survey and the Washington State Department of Ecology. The reason for collecting these data is to provide a regional synthesis of the offshore geology to support a wide variety of management decisions and to provide a basis for further process-oriented investigations.
    Supplemental_Information:
    Roberts, R.W., 1974, Marine sedimentological data of the Washington continental shelf: University of Washington, Department of Oceanography Special Report 57, 129p.

    Nittrouer, C.A., 1978, The process of detrital sediment accumulation in a continental shelf environment: an examination of the Washington shelf: PhD Thesis, University of Washington, Seattle, WA. 243p.

    Smith, J.M., Messmer, L.W., Phipps, J.B., Samuelson, D.F., and Schermer, E.D., 1980, Grays Harbor and Chehalis River improvements to navigation environmental studies - Grays Harbor ocean disposal study: literature review and preliminary benthic sampling: U.S. Army Corps of Engineers Internal Report.

  1. How should this data set be cited?

    Cross, VeeAnn A. , 20010716, Grid Representing the Landward DEM and the Present Day Bathymetry of the Columbia River within the SWCES Study Area: U.S. Geological Survey, Woods Hole, MA.

    This is part of the following larger work.

    Twichell, David C. , and Cross, VeeAnn A. , 20011000, Holocene Evolution of the Southern Washington and Northern Oregon Shelf and Coast: Geologic Discussion and GIS Data Release: U.S. Geological Survey Open-File Report Report 01-076.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -124.589213
    East_Bounding_Coordinate: -122.892198
    North_Bounding_Coordinate: 47.348056
    South_Bounding_Coordinate: 45.935467

  3. What does it look like?

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

    Calendar_Date: 16-Jul-2001
    Currentness_Reference: publication date

  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 779 x 641 x 1, 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: 0.999600
      Longitude_of_Central_Meridian: -123.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 200.000000
      Ordinates (y-coordinates) are specified to the nearest 200.000000
      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.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum of 1988
      Altitude_Resolution: 200
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Implicit coordinate
      Depth_System_Definition:
      Depth_Datum_Name: Mean lower low water
      Depth_Resolution: unknown
      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?

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

    David C. Twichell
    USGS
    Oceanographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543
    USA

    508-548-8700 (voice)
    508-457-2310 (FAX)
    dtwichell@usgs.gov

Why was the data set created?

This GIS overlay is a component of the Southwest Washington Coastal Erosion ArcView GIS database. This grid coverage represents the landward DEM of the study area as well as the Columbia River present day bathymetry. This grid was used to merge with the 1000 year surfaces to form a more realistic looking surface.

How was the data set created?

  1. From what previous works were the data drawn?

    SWCES DEM (source 1 of 1)
    Daniels, Richard C. , Unpublished Material, Personal Communication.

    Other_Citation_Details:
    Acquired from the Washington State Department of Ecology in Olympia, Washington.
    Type_of_Source_Media: electronic mail system
    Source_Contribution:
    The DEM supplied by the Department of Ecology incorporates several data sources including published DEM data as well as LIDAR data acquired as a result of the SWCES.

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

    Date: 01-Mar-2001 (process 1 of 1)
    The original NOS point bathymetry data was gridded at a 200m cell size to correspond with all the other grids in this study. This grid was then clipped to the particular area of interest. The Washington State Department of Ecology supplied the landward DEM that was resampled to a 200m cell size. This DEM was then merged with the gridded bathymetry from the Columbia River.

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

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

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

    This data is complete for this particular study.

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

    Consistent

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:
The U.S. Geological Survey must be referenced as the originator of the dataset in any future products or research derived from these data.

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

    David C. Twichell
    USGS
    Oceanographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543
    USA

    508-548-8700 (voice)
    508-457-2310 (FAX)
    dtwichell@usgs.gov

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

  3. What legal disclaimers am I supposed to read?

    This Compact Disc-Read Only Memory (CD-ROM) publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitude or imply its endorsement, recommendation, or favoring by the United States Governemnt or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    Capable of reading or translating ESRI grid format.

Who wrote the metadata?

Dates:
Last modified: 15-Aug-2001

Metadata author:
VeeAnn A. Cross
USGS
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543
USA

508-548-8700 (voice)
508-457-2310 (FAX)
vatnipp@usgs.gov

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

Metadata extensions used:

Generated by mp (URL: http://geology.usgs.gov/tools/metadata/tools/doc/mp.html ) version 2.7.3 on Fri Nov 16 16:29:44 2001