Acoustic backscatter from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington

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Frequently anticipated questions:

What does this data set describe?

Title:
Acoustic backscatter from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington
Abstract:
This part of the USGS data release presents acoustic backscatter data for the Columbia River Mouth, Oregon and Washington. The acoustic backscatter data of the Columbia River Mouth, Oregon and Washington were collected by the U.S. Geological Survey (USGS). Mapping was completed in 2013, using a 234-kHz SEA SWATHPlus interferometric system. These data are not intended for navigational purposes.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at: http://cmgds.marine.usgs.gov/fan_info.php?fan=S0313WO
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
  1. How might this data set be cited?
    Gelfenbaum, Guy, Finlayson, David, and Dartnell, Peter, 2015, Acoustic backscatter from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington: data release DOI:10.5066/F7T72FHB, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Gelfenbaum, Guy, Finlayson, David, and Dartnell, Peter, 2015, Bathymetry and backscatter from 2013 interferometric swath bathymetry systems survey of Columbia River Mouth, Oregon and Washington: data release DOI:10.5066/F7T72FHB, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -124.11
    East_Bounding_Coordinate: -123.92
    North_Bounding_Coordinate: 46.29
    South_Bounding_Coordinate: 46.20
  3. What does it look like?
    http://www.sciencebase.gov/catalog/file/get/5f00c7e782ce0afb2445d6ec?name=USGS_CR_acousticBackscatter.png&allowOpen=true (PNG)
    Greyscale image map showing acoustic backscatter of the Columbia River mouth off Oregon and Washington. Lighter tones show stronger, high-intensity backscatter indicating harder and rougher bottom types such as rocky outcrops or coarse sediment; darker tones show weaker, low-intensity backscatter indicating softer bottom types such as fine sediment.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 06-May-2013
    Ending_Date: 18-Jun-2013
    Currentness_Reference:
    ground condition at time data were collected
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: GeoTIFF
  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, 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: -123.00000
      Latitude_of_Projection_Origin: 0.00000
      False_Easting: 500000.0
      False_Northing: 0.00
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 1.0
      Ordinates (y-coordinates) are specified to the nearest 1.0
      Planar coordinates are specified in Meters
      The horizontal datum used is NAD83.
      The ellipsoid used is GRS80.
      The semi-major axis of the ellipsoid used is 6378137.00.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    The USGS Columbia River Mouth backscatter data were originally archived as a GeoTIFF image with the following attributes: 
    Cell size = 1.0
Number of rows = 9386
Number of columns = 21067

Data type = floating point

Boundary
Xmin = 413360
Xmax = 434427
Ymin = 5115831
Ymax = 5125217

Statistics
Minimum value = -11.12
Maximum value = 65546.12
Mean = 32046.10
Standard deviation = 9795.75

Coordinate system description
Projection  UTM
Zone  10
Datum  NAD83 (GEOID12A)
Units  meter
    Entity_and_Attribute_Detail_Citation: none

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Guy Gelfenbaum
    • David Finlayson
    • Peter Dartnell
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    Attn: PCMSC Science Data Coordinator
    2885 Mission Street
    Santa Cruz, CA
    US

    831-427-4747 (voice)
    pcmsc_data@usgs.gov

Why was the data set created?

These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify bathymetric features.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2015 (process 1 of 4)
    The USGS R/V Parke Snavely was equipped with an Applanix Position and Orientation System for Marine Vessels (POS/MV) inertial motion unit (IMU) for the duration of the survey. The POS/MV received Differentially Corrected Global Positioning System (DGPS) aided positional navigation from dual Trimble model 4000 DGPS receivers, and commercial C-Nav satellite differential stations. The DGPS data were combined with the inertial vessel motion measurements (pitch, roll, and heading) directly within the POS/MV hardware so that high-precision position and attitude corrections were fed in real time to the sonar acquisition equipment. Sound velocity measurements were collected continuously with an Applied Micro Systems Micro sound velocimeter (SV) deployed on the transducer frame for real-time sound velocity adjustments at the transducer-water interface. Additionally, water column sound velocity profiles (SVP) were collected approximately every 2 hours throughout each survey day with an Applied Micro Systems, SvPlus 3472. DGPS data and measurements of vessel motion were combined in the POS/MV hardware to produce a high-precision vessel attitude packet. This packet was transmitted to the Swath Processor acquisition software in real time and combined with instantaneous sound velocity measurements at the transducer head before each ping. The returned samples were projected to the seafloor using a ray-tracing algorithm working with the previously measured sound-velocity profiles in SEA Swath Processor. A series of statistical filters were applied to the raw samples that isolated the seafloor returns from other spurious targets in the water column. Finally, the processed data were stored line-by-line in both raw (.sxr) and processed (.sxp) trackline files. The raw 16-bit backscatter data recorded simultaneously with bathymetry by the SWATHplus system was georeferenced and gain-normalized by the program SXPEGN written by the USGS to enhance the backscatter imagery. The program normalizes for time-varying signal loss and beam directivity differences. The resulting normalized amplitude values are re-scaled to 16 bit, and gridded into a GeoJPEG using GRID Processor Software supplied by SEA. The image was imported into ESRI GIS software and projected to North American Datum of 1983. The image was then converted to a GeoTIFF file using ESRI GIS software. Person who carried out this activity:
    Peter Dartnell
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    United States

    831-460-7415 (voice)
    pdartness@usgs.gov
    Date: 25-Nov-2019 (process 2 of 4)
    Extraneous text removed from Semi-Major Axis tag. Point of Contact and Metadata Contact were updated to PCMSC static contact information, and Data Processing Contact information was added. No data or data information were changed. This updated metadata file was also slipped inside the zip file containing the data. Person who carried out this activity:
    Susan A Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    United States

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 04-Oct-2025 (process 3 of 4)
    Data and metadata files were moved to a different location on ScienceBase, resulting in a change of ID number in the Online_Linkage and Network_Resources URLs of the metadata. In addition, edits were made as needed to bring the metadata up to current PCMSC standards including adding disclaimers, and refining keywords. No data were changed, however the metadata file is now only found at the top level download and not tucked inside the data zip (to allow easier updates in the future). Users are advised to compare the metadata date of this file to any similar file to ensure they are using the most recent version. Person who carried out this activity:
    Susan A Cochran
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission St.
    Santa Cruz, CA
    United States

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 19-Oct-2020 (process 4 of 4)
    Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?

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

  1. How well have the observations been checked?
    Not applicable for raster data.
  2. How accurate are the geographic locations?
    Horizontal_Positional_Accuracy_Report: Estimated to be no less than 2 m, owing to water depth and total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations.
  3. How accurate are the heights or depths?
    Vertical_Positional_Accuracy_Report: Not applicable to imagery
  4. Where are the gaps in the data? What is missing?
    Complete
  5. How consistent are the relationships among the observations, including topology?
    Unspecified

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:
USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data. This information is not intended for navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - Science Base
    U.S. Geological Survey
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? Data are available in a zip file (USGS_CR_backscatter_UTM10_NAD83.zip) containing a GeoTIFF raster (USGS_CR_backscatter_UTM10_NAD83.tif), along with the associated Tiff World File (USGS_CR_backscatter_UTM10_NAD83.tfw). The data zip is accompanied by FGDC-compliant metadata and a browse graphic.
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    The downloadable data file has been compressed with the "zip" command and can be unzipped with WinZip (or other tool) on Windows systems. To utilize these data, the user must have software capable of uncompressing the WinZip file and importing and viewing an Esri ArcMap TIFF.

Who wrote the metadata?

Dates:
Last modified: 19-Oct-2020
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA
US

831-427-4747 (voice)
pcmsc_data@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/pcmsc/DataReleases/ScienceBase/DR_F7T72FHB/USGS_CR_backscatter_UTM10_NAD83.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:17:22 2021