Acoustic backscatter data from USGS Field Activity S-8-08-SC, northern Santa Barbara Channel, southern California

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Frequently anticipated questions:

What does this data set describe?

Title:
Acoustic backscatter data from USGS Field Activity S-8-08-SC, northern Santa Barbara Channel, southern California
Abstract:
Acoustic backscatter data were collected by the U.S. Geological Survey in July 2008 in the northern Santa Barbara Channel in southern California. Data were collected aboard the R/V Parke Snavely, during USGS Field Activity S-9-08-SC, using a bathymetric sidescan system.
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=S808SC
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Dartnell, Peter, Finlayson, David, Conrad, James, Cochrane, Guy, and Johnson, Samuel, 2010, Acoustic backscatter data from USGS Field Activity S-8-08-SC, northern Santa Barbara Channel, southern California: Open-File Report 2009-1289, 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, Finlayson, David, Conrad, James, Cochrane, Guy, and Johnson, Samuel, 2010, Bathymetry and Acoustic Backscatter: Northern Santa Barbara Channel, Southern California: Open-File Report 2009-1289, 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: -120.5000000
    East_Bounding_Coordinate: -120.0000000
    North_Bounding_Coordinate: 34.50000000
    South_Bounding_Coordinate: 34.25000000
  3. What does it look like?
    http://pubs.usgs.gov/of/2009/1289/images/usgs2008_mos.pdf (PDF)
    Map showing backscatter imagery, northern Santa Barbara Channel (5 Mb)
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 08-Jul-2008
    Ending_Date: 23-Jul-2008
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Raster
  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 2.0
      Ordinates (y-coordinates) are specified to the nearest 2.0
      Planar coordinates are specified in Meters
      The horizontal datum used is NAD83.
      The ellipsoid used is NAVD88.
      The semi-major axis of the ellipsoid used is 6378137.00.
      The flattening of the ellipsoid used is 1/0.003352811.
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    The backscatter data was originally archived as an ESRI grid with the following attributes: 
    Cell size = 2.0
Number of rows = 6001
Number of columns = 11001

Data type = floating point

Boundary
Xmin = 755999.0
Xmax = 778001.0
Ymin = 3807999.0
Ymax = 3820001.0

Statistics
Minimum value = 12165.5
Maximum value = 58482.87
Mean = 31953.76
Standard deviation = 3448.79

Coordinate system description
Projection  UTM
Zone  10
Datum  NAD83
Units  meters
    These data are published in this report in three different formats with the following attributes, 
    BACKSC.TIFF
Imageformat = TIFF
Image type = grayscale
Image colormap = false
Image compressed = false
Image rotate = false

Image depth = 16
Image bands = 1
Number of columns = 6001
Number of rows = 11001
Pixel size DX = 2.0
Pixel size DY = 2.0

Boundary
Xmin = 755999.0
Xmax = 778001.0
Ymin = 3807999.0
Ymax = 3820001.0

BACKSC.XYZ
XYZ file (x-coord, y-coord, depth) created from the ESRI grid using the command "GRIDPOINT".

BACKSC.ASC
ASCIIRASTER files created from the ESRI grid using the command "GRIDASCII".
    Entity_and_Attribute_Detail_Citation: USGS

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Peter Dartnell
    • David Finlayson
    • James Conrad
    • Guy Cochrane
    • Samuel Johnson
  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?

These data are intended for science researchers, students, policy makers, and the general public. The data can be used with geographic information systems (GIS) or other software to display the bathymetry data.

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: 2009 (process 1 of 3)
    The backscatter data were collected using 234.5 kHz SEA (AP) Ltd. SWATHplus-M phase-differencing sidescan sonar aboard the USGS R/V Parke Snavely. The survey vessel was equipped with a CodaOctopus F190 attitude and position system. This system combines Real Time Kinematic (RTK) Global Positioning System (GPS) data (2 cm error ellipse) with inertial motion measurements so that high-precision position and attitude corrections are fed in real-time to the sonar acquisition equipment. Up to 10 pings per second are transmitted with each ping consisting of 2048 samples per side (port and starboard). The returned samples were projected to the seafloor using a ray-tracing algorithm working with the previously measured sound velocity profiles. A series of statistical filters were applied to the raw samples that discriminate the seafloor returns from other unintended targets in the water column. Finally, the processed data were stored, line-by-line in processed trackline files. The individual soundings stored in the processed trackline files were combined into a 2-m resolution rasters in the Grid Processor software. The 2-m binned amplitude values were exported from Grid Processor as an XYZ point cloud. The WGS84 (G1150) ellipsoidal coordinates of the survey were transformed into NAD83 (CORS96) ellipsoidal coordinates using a 7-parameter Helmert transformation available in the CS2CS program in the Proj.4 library (Version 442 for 32-bit Windows). The seven required parameters for the procedure were calculated using an Epoch date of 8 July 2008 according to procedure outlined in Soler and Snay (2004). Finally, the resulting NAD83 (CORS96) elevation postings were transformed into NAVD 1988 using the NOAA VDatum (Version 2.2.4) with the Geoid03 model. A script divided the 2-m binned point cloud into 2 x 2 km tiles. Each tile was gridded using Surfer (Version 9.2.397) and a linear Krigging algorithm and 0.20 cm nugget (the mean standard deviation of all 2-m cells in the survey). Finally, the 2-km tiles were mosaicked into a contiguous raster and converted to an Esri GRID. Person who carried out this activity:
    David Finlayson
    U.S. Geological Survey
    Operational Geologist
    2885 Mission Street
    Santa Cruz, CA
    USA

    (831) 427-4757 (voice)
    dfinlayson@usgs.gov
    Date: 31-Jan-2020 (process 2 of 3)
    Edits were made to bring the metadata up to current PCMSC standards including adding a doi# link, correcting typos, refining keywords, and using current access and distribution liability statements. Point of Contact and Metadata Contact information sections were changed to static PCMSC contact information. No data were changed. 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 Street
    Santa Cruz, CA
    United States

    831-460-7545 (voice)
    scochran@usgs.gov
    Date: 19-Oct-2020 (process 3 of 3)
    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?
    0.5 meters
  3. How accurate are the heights or depths?
    0.05 percent of the water depth.
  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 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
    345 Middlefield Rd MS-532
    Menlo Park, CA
    USA

    (650) 329-4309 (voice)
  2. What's the catalog number I need to order this data set?
  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?

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

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/SeriesReports/OFR/OFR_2009-1289/S-8-08-SC_backscatter_metadata.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:17:52 2021