Acoustic-backscatter data for Santa Cruz Harbor, California collected during USGS field activity 2022-609-FA

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Frequently anticipated questions:

What does this data set describe?

Acoustic-backscatter data for Santa Cruz Harbor, California collected during USGS field activity 2022-609-FA
1-m resolution acoustic-backscatter data were collected during a January 2022 SWATHPlus survey in and near the Santa Cruz harbor, California. Data were collected and processed by the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC) with fieldwork activity number 2022-609-FA. The 1-m acoustic-backscatter data are provided as a GeoTIFF file.
Additional information about the field activity from which these data were derived is available online at:
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 Jaffe, Bruce E., 20230322, Acoustic-backscatter data for Santa Cruz Harbor, California collected during USGS field activity 2022-609-FA: data release DOI:10.5066/P9IY4ZEK, 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 Jaffe, Bruce E., 2023, Bathymetry and acoustic backscatter data for Santa Cruz Harbor, California collected during USGS field activity 2022-609-FA: data release DOI:10.5066/P9IY4ZEK, 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: -122.017
    East_Bounding_Coordinate: -121.998
    North_Bounding_Coordinate: 36.973
    South_Bounding_Coordinate: 36.956
  3. What does it look like? (JPEG)
    Quick view image of the Santa Cruz harbor acoustic-backscatter data.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 26-Jan-2022
    Ending_Date: 26-Jan-2022
    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 1907 x 1646 x 1, type Grid Cell
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      UTM_Zone_Number: 10
      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 North American Datum of 1983, 2011 realization (NAD83(2011)).
      The ellipsoid used is GRS80.
      The semi-major axis of the ellipsoid used is 6378137.00.
      The flattening of the ellipsoid used is 1/298.257222101.
  7. How does the data set describe geographic features?
    acoustic backscatter value (Source: Producer defined)
    The complete 1-m resolution image "SCharbor_1m_backscatter_NAD83.tif" was originally archived as a TIFF image with the following attributes.
    Cell size = 1.0
    Number of rows = 1907
    Number of columns = 1646
    Data type = floating point
    Xmin = 587546
    Xmax = 589192
    Ymin = 4090475
    Ymax = 4092382
    Minimum value = 0
    Maximum value = 65535
    Mean = 22703.35
    Standard deviation = 5260.18
    Coordinate system description
    Projection:  UTM
    Zone:  10
    Datum:  NAD83(2011)
    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
    • Bruce E. Jaffe
  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)

Why was the data set created?

On January 15, 2022, an underwater volcanic eruption near Tonga generated a Pacific Ocean wide tsunami that impacted the California coast including northern Monterey Bay and the Santa Cruz harbor. The USGS, PCMSC conducted a bathymetric survey shortly after the tsunami to document any seafloor features that may have been created by the tsunami. 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. These data are not intended to be used for navigation.

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: 2023 (process 1 of 1)
    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 San Lorenzo. 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 day with a Castaway sound velocimeter. Post-processed POS-MV Smoothed Best Estimate of Trajectory (SBET) files were merged with the survey line files using BathySwath software and then the line files were imported into SonarWiz software. Backscatter imagery was generated using SonarWiz processing techniques. The backscatter image was exported as an Erdas Imagine file in UTM-10, WGS-84 coordinates. The image was re-projected to UTM-10, NAD83 coordinates using "Project Raster" tool in ArcToolbox. The new backscatter was then exported as a geoTIFF file in UTM zone 10, NAD-83(2011) coordinates.
  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?
    No accuracy assessment was made on the backscatter date
  2. How accurate are the geographic locations?
    The Applanix POS-MV post-processed horizontal positional accuracy is about 0.1 m with roll and pitch accuracies of about 0.02 degrees ( The SWATHPlus sonar system (234 kHz) has an across track resolution of about 5 cm ( 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.
  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 - CMGDS
    2885 Mission Street
    Santa Cruz, CA

    831-427-4747 (voice)
  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 are accompanied by 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?
  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?

Last modified: 22-Mar-2023
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)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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