Acoustic-backscatter data collected in 2016 offshore the Elwha River mouth, Washington, during USGS Field Activity 2016-605-FA

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

Frequently anticipated questions:

What does this data set describe?

Title:
Acoustic-backscatter data collected in 2016 offshore the Elwha River mouth, Washington, during USGS Field Activity 2016-605-FA
Abstract:
These metadata describe acoustic-backscatter data collected during a 2016 SWATHPlus-M survey offshore the Elwha River mouth, Strait of Juan de Fuca, Washington. Data were collected and processed by the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC) with fieldwork activity number 2016-605-FA. The acoustic-backscatter data are provided as a GeoTIFF image in UTM, zone 10, NAD83 coordinates.
Supplemental_Information:
Additional information about the field activity from which these data were derived is available online at:
https://cmgds.marine.usgs.gov/fan_info.php?fan=2016-605-FA
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?
    Dartnell, Peter, and Warrick, Jonathan A., 20201104, Acoustic-backscatter data collected in 2016 offshore the Elwha River mouth, Washington, during USGS Field Activity 2016-605-FA: data release DOI:10.5066/P9YVVAMT, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Dartnell, Peter, and Warrick, Jonathan A., 2020, Bathymetry and acoustic-backscatter data collected in 2016 offshore the Elwha River mouth, Washington, during USGS Field Activity 2016-605-FA: data release DOI:10.5066/P9YVVAMT, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -123.610
    East_Bounding_Coordinate: -123.470
    North_Bounding_Coordinate: 48.160
    South_Bounding_Coordinate: 48.130
  3. What does it look like?
    2016_Elwha_backscatter_QV.jpg (JPEG)
    Quickview image of acoustic-backscatter data collected in 2016 offshore the Elwha River mouth, Strait of Juan de Fuca, Washington
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 13-Feb-2016
    Ending_Date: 18-Feb-2016
    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 2713 x 4974, 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: 0.0
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 2.0
      Ordinates (y-coordinates) are specified to the nearest 2.0
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 1983 (2011).
      The ellipsoid used is Geodetic Reference System 96.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257.
  7. How does the data set describe geographic features?
    Normalized Acoustic Backscatter Amplitude
    The raw 16-bit backscatter recorded simultaneously with the bathymetry by the SWATHplus was gain-normalized by the program SonarWiz. The program normalizes for time-varying signal loss and beam directivity differences. The resulting normalized amplitude values are re-scaled to 16-bit, exported as an Imagine image. Normalized acoustic backscatter shows the relative strength of the acoustic signal returned from the seafloor. (Source: Producer defined)
    Entity_and_Attribute_Overview:
    The complete 2016 2-m resolution image "2016_ElwhaDelta_2m_backscatter_UTM10_NAD83.tif" was originally archived as a TIFF image with the following attributes. 
    Cell size = 1.0
Number of rows = 2713
Number of columns = 4974

Data type = floating point

Boundary
Xmin = 454923
Xmax = 464873
Ymin = 5329866
Ymax = 5335293

Statistics
Minimum value = 63.98
Maximum value = 146.00
Mean = 99.81
Standard deviation = 9.88

Coordinate system description
Projection  UTM
Zone  10
Datum  NAD83
Units  meter
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Peter Dartnell
    • Jonathan A. Warrick
  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

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

Why was the data set created?

Sonar-based surveys of the seafloor around the Elwha River mouth, Strait of Juan de Fuca, Washington were conducted to map changes that have occurred following sediment input from dam removals from the Department of the Interior's Elwha River Restoration Project. This project resulted in the removal of two large dams on the Elwha River during 2011-2014, which released millions of tonnes of sediment to the river and coast. Similar sonar-based surveys were conducted before the dam removals in 2008 and 2010 by the USGS, and these pre-removal surveys may be used for comparisons with the data provided herein. Collaborative partners in this work include the Lower Elwha Klallam Tribe.

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: 2016 (process 1 of 3)
    The Swath survey was conducted with a SWATHplus-M 234-kHz interferometric side-scan sonar system pole-mounted on the U.S. Geological Survey (USGS) R/V Parke Snavely. During the mapping mission, an Applanix POS-MV (Position and Orientation System for Marine Vessels) was used to position the vessel during data collection and it also accounted for vessel motion such as heave, pitch, and roll. The POS-MV also recorded position and vessel motion parameters for later post-processing. Sound-velocity profiles were collected throughout the survey days with a Castaway sound velocimeter. Post-processed Applanix POS-MV Smoothed Best Estimate of Trajectory (SBET) data were merged with each original survey line file using Bathyswath processing software to create new post-processed survey line files. The post-processed line files were imported into SonarWiz software (version 6) for backscatter processing. A processed backscatter grid was exported as an Imagine image in UTM zone 10 WGS84 coordinates. The image was imported into ArcGIS and projected to UTM zone 10, NAD83 coordinates using the ArcTools project raster function. The backscatter image was then exported as a GeoTIFF image in UTM zone 10, NAD83 coordinates.
    Date: 17-Mar-2021 (process 2 of 3)
    Corrected working URL links to cmgds data repository to the actual published links Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan A. Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 13-Oct-2021 (process 3 of 3)
    Performed minor edits to the metadata to correct typos. No data were changed Person who carried out this activity:
    U.S. Geological Survey
    Attn: Susan A. Cochran
    Geologist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7545 (voice)
    scochran@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?
    The SWATHPlus-M sonar system (234 kHz) depth accuracy reduces with horizontal range. The system has an estimated vertical depth uncertainty ranging from about 0.05 m to 0.30 m over a horizontal range of 0 to 90 m (https://www.iter-systems.com/wp-content/uploads/2020/03/ETD_2002_Bathyswath-2_Tech-info_EN.pdf). Accuracies of final products may be lower due to 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.
  2. How accurate are the geographic locations?
    Uncertainty in the horizontal position of each sounding is a function of the total uncertainty propagated through each of the following component instruments: 1) vessel GPS, 2) intertial motion unit (IMU), 3) water sound velocity model, and 4) beam spreading in the water column. Assuming no systematic errors in the measurement instruments themselves, beam spreading is the dominate source of positional uncertainty. The 1-degree sonar beam of the SWATHplus-M results in horizontal uncertainty ranging from 0.10 m at 10 m slant range, to about 0.45 m at 50 m slant range. Accuracies of final products may be lower due to data processing that includes sounding cleaning, gridding, and datum transformations.
  3. How accurate are the heights or depths?
    Not applicable to backscatter data.
  4. Where are the gaps in the data? What is missing?
    Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    No formal logical accuracy tests were conducted

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 originators of the dataset and in products derived from these data. This information is not intended for navigation purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey, Pacific Coastal and Marine Science Center
    2885 Mission Street
    Santa Cruz, CA

    1-888-427-4747 (voice)
    pcmsc_data@usgs.gov
  2. What's the catalog number I need to order this data set? These data are available in GeoTIFF format, including a tif world file (.tfw) and CSDGM FGDC-compliant metadata.
  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?
    • Availability in digital form:
      Data format: Downloadable zip file contains the TIFF (.tif) version of the backscatter data and a projection file (.tfw). in format GeoTIFF (version ArcMap (version 10.3.1)) Size: 5
      Network links: https://doi.org/10.5066/P9YVVAMT
    • Cost to order the data: None.

  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 a GeoTIFF file.

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2021
Metadata author:
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Attn: PCMSC Science Data Coordinator
2885 Mission Street
Santa Cruz, CA

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/CMGDS_DR_tool/DR_P9YVVAMT/2016_ElwhaDelta_2m_backscatter_UTM10_NAD83_metadata.faq.html>
Generated by mp version 2.9.50 on Thu Oct 14 14:47:20 2021