Sidescan-sonar Image of the Western Portion of the John Day Reservoir - Geographic Coordinates

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Frequently-anticipated questions:

What does this data set describe?
    Title:
    Sidescan-sonar Image of the Western Portion of the John Day Reservoir - Geographic Coordinates
    Abstract:
    A two-week field operation was conducted in the John Day Reservoir on the Columbia River to image the floor of the pool, to measure the distribution and thickness of post-impoundment sediment, and to verify these geophysical data with video photography and bottom sediment samples. The field program was a cooperative effort between the USGS Coastal and Marine Geology Team of the Geologic Division and the USGS Columbia River Research Laboratory of the Biological Resources Division. The data collection was completed aboard the R/V ESTERO during September 13-27, 2000. The interest in sediment accumulation in the reservoir was two-fold. First, it was unknown how effective this reservoir was as a sediment trap to material that otherwise would have been transported down-river to the estuary and eventually to the ocean. The recent erosion of beaches along the Washington coast has been attributed to a decreased contribution of sediment from the Columbia River to the coastal system due to the damming of the river. Second, sediment accumulation on the floors of reservoirs along the Columbia River has been suggested to be diminishing salmon spawning grounds. The extent of changes in habitat since construction of the John Day Dam, however, had not been documented. Common data sets were needed to address both of these questions, and for these reasons this geophysical and sampling program was undertaken.

  1. How should this data set be cited?

    Cross, VeeAnn A. , and Twichell, David C. , 2004, Sidescan-sonar Image of the Western Portion of the John Day Reservoir - Geographic Coordinates:.

    Online Links:

    This is part of the following larger work.

    Cross, VeeAnn A. , and Twichell, David C. , 2004, Geophysical, Sedimentologic, and Photographic Data from the John Day Reservoir, Washington and Oregon: Data Archive and Preliminary Discussion: Open-File Report 2004-1014, U.S. Geological Survey, Woods Hole Science Center, Woods Hole, MA.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -120.691405
    East_Bounding_Coordinate: -120.016737
    North_Bounding_Coordinate: 45.816037
    South_Bounding_Coordinate: 45.685288

  3. What does it look like?

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

    Beginning_Date: 11-Sep-2000
    Ending_Date: 22-Sep-2000
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: remote-sensing image

  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 7266 x 26139 x 1, type Pixel

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

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000018. Longitudes are given to the nearest 0.000026. Latitude and longitude values are specified in Decimal degrees.

      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.

  7. How does the data set describe geographic features?

    Band_1

    ObjectID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Value

    Red

    Green

    Blue

    Entity_and_Attribute_Overview:
    The pixel value represents the DN return value of the sidescan-sonar system. A high value (ie 254) indicates a highly reflective lake floor surface, while a low value (ie 0) indicates low reflectance.

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
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov

Why was the data set created?
This sidescan-sonar imagery is used to map the morphology of the reservoir floor and determine the extent of sediment distribution on the reservoir floor.

How was the data set created?
  1. From what previous works were the data drawn?

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

    (process 1 of 5)
    Sidescan sonar imagery was collected using a Datasonics SIS-1000 sidescan sonar system and logged to a Triton QMIPS data logging computer.

    (process 2 of 5)
    The digital sidescan data were then processed and mapped to provide proper geographic locations of features identified in the imagery. The processing steps included subsampling the raw sidescan data using a median filtering routine to suppress speckle noise and reduce file size, and correct for slant-range distortion, signal attenuation, and dropped sonar lines using XSonar (Danforth et al., 1991). After these processing steps, the imagery was mapped into its proper geographic location using techniques summarized by Paskevich (1996). Individual sidescan swaths were mapped with each pixel geographically positioned at a resolution of 2 m/pixel. The projection for this mapping was Washington State Plane South, NAD83. Processing the data up to this point was done be VeeAnn Cross.

    Data sources used in this process:

    • Danforth, W.W., O'Brien, T.F., and Schwab, W.C., 1991, USGS image processing system: near real-time mosaicking of high-resolutoin sidescan-sonar data: Sea Technology, Jan., 1991, p. 54-59.
    • Paskevich, V.F., 1996, MAPIT: An improved method for mapping digital sidescan sonar data using the Woods Hole Image Processing System (WHIPS) software: U.S. Geological Survey Open-File Report 96-281, 73p.

    (process 3 of 5)
    Non-overlapping swaths were then brought into the remote sensing software package PCI. The techniques for generating the composite digital sidscan mosaic are summarized by Paskevich (1992). Processing of the data from this point on was done by David C. Twichell.

    Data sources used in this process:

    • Paskevich, V.F., 1992, Digital mapping of sidescan sonar data with the Woods Hole Image Processing System software: U.S. Geological Survey Open-File Report 92-536, 87p.

    (process 4 of 5)
    Once the mosaics were completed, the mosaic was trimmed based on the reservoir shoreline as supplied by the USGS BRD office in Cook Washington. This trimmed mosaic was then enhanced and written to a PCI channel that had a white background.

    (process 5 of 5)
    The Washington State Plane South, NAD83 projected image was the reprojected to Geographic coordinates using BlueMarble's Geographic Transformer software. Transform parameters used a resolution of 2m/pixel and a central latitude of 45.8N.

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?

    The ship was navigated with P-CODE GPS. The towfish was deployed at approximately the same depth each day, with little variation during the course of the survey. Therefore range to fish values are assumed consistent and accurate.

  3. How accurate are the heights or depths?

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

    All imagery necessary to map the lake floor was used.

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

    All these data were collected with the same sidescan-sonar towfish. The data were acquired at 1200m and 800m swath widths.

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
    U.S. Geological Survey
    Oceanographer
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2266 (voice)
    (508) 457-2310 (FAX)
    dtwichell@usgs.gov

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

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    These data were 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 constitute or imply its endorsement, recommendation, or favoring by the United States government 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 in this report 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?

Who wrote the metadata?
Dates:
Last modified: 09-Mar-2004

Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700 x2251 (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 version 2.7.3 on Tue Mar 09 14:08:18 2004