1-meter sidescan-sonar mosaic image collected by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA in 2014 (GeoTIFF, UTM Zone 18N, WGS 84)

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Frequently anticipated questions:


What does this data set describe?

Title:
1-meter sidescan-sonar mosaic image collected by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA in 2014 (GeoTIFF, UTM Zone 18N, WGS 84)
Abstract:
The Delmarva Peninsula is a 220-kilometer-long headland, spit, and barrier island complex that was significantly affected by Hurricane Sandy. A U.S. Geological Survey cruise was conducted in the summer of 2014 to map the inner continental shelf of the Delmarva Peninsula using geophysical and sampling techniques to define the geologic framework that governs coastal system evolution at storm-event and longer timescales. Data collected during the 2014 cruise include swath bathymetry, sidescan sonar, chirp and boomer seismic-reflection profiles, acoustic Doppler current profiler, and sample and bottom photograph data. Processed data in raster and vector format are released here for the swath bathymetry, sidescan sonar, and seismic-reflection profiles. More information about the USGS survey conducted as part of the Hurricane Sandy Response-- Geologic Framework and Coastal Vulnerability Study can be found at the project website or on the WHCMSC Field Activity Web pages: https://woodshole.er.usgs.gov/project-pages/delmarva/ and https://cmgds.marine.usgs.gov/fan_info.php?fan=2014-002-FA
  1. How might this data set be cited?
    U.S. Geological Survey, 2015, 1-meter sidescan-sonar mosaic image collected by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA in 2014 (GeoTIFF, UTM Zone 18N, WGS 84): data release DOI:10.5066/F7MW2F60, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Pendleton, E.A., Ackerman, S.D., Baldwin, W.E., Danforth, W.W., Foster, D.S., Thieler, E.R., and Brothers, L.L., 2015, High-resolution geophysical data collected along the Delmarva Peninsula 2014, U.S. Geological Survey Field Activity 2014-002-FA: data release DOI:10.5066/F7MW2F60, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.388328
    East_Bounding_Coordinate: -74.906600
    North_Bounding_Coordinate: 38.435211
    South_Bounding_Coordinate: 37.797342
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2014-002-FA/data/backscatter/Delmarva_sss.png (png)
    thumbnail image of regional sidescan sonar mosaic for Delmarva Peninsula
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 27-Jun-2014
    Ending_Date: 25-Jul-2014
    Currentness_Reference:
    ground condition; data were not collected on 20140702-20140704; 20140709; and 20140714-20140715 due to weather.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  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 Pixel
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 18
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -75
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000
      False_Northing: 0
      Planar coordinates are encoded using row and column
      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 D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    There are no attributes associated with a GeoTIFF image. Image pixel values contain acoustic reflectivity values normalized to an 8-bit data range. Low-backscatter is represented by dark tones (low values) and high-backscatter is represented by bright tones (high values). The background color is set to 0 and can be turned off without removing data values.
    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)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
    U.S. Geological Survey
  3. To whom should users address questions about the data?
    Elizabeth Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA

    (508) 548-8700x2259 (voice)
    (508)-457-2310 (FAX)
    ependleton@usgs.gov

Why was the data set created?

These 1-m backscatter mosaic were created from 100 kHz Klein sidescan sonar data. Backscatter mosaic images are useful geophysical datasets for geologic framework studies. These data can be used in conjunction with other geophysical and sample data to identify sea-floor morphology and sediment texture.

How was the data set created?

  1. From what previous works were the data drawn?
    raw backscatter (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, raw Klein sidescan sonar data in XTF format.

    Type_of_Source_Media: disc
    Source_Contribution:
    Data acquisition at sea: Sidescan sonar data were collected with a Klein 3000 dual frequency (132/445 kHz) sidescan-sonar towfish on the M/V Scarlet Isablella. The sonar was towed from the stern A-frame of the vessel. A 3PS digital block cable counter was used to measure the amount of tow cable deployed, and cable out values were transmitted via serial connection to the SonarPro acquisition software (versions 10.0) for layback calculation. Tracklines are generally spaced 200m apart.
  2. How were the data generated, processed, and modified?
    Date: 30-Jul-2014 (process 1 of 5)
    Raw XTF format Klein sidescan data (100 kHz) were imported into SonarWiz version 5.07.0008 software on the M/V Scarlet Isabella for preliminary shipboard processing. Each line received a bottom tracking correction to remove the water column at nadir. SonarWiz has an automatic bottom tracking algorithm that generally performs well in most coastal settings. Auto tracking parameters for this survey were set to a blanking value of 2; a duration value of 5; and a threshold of 6 with line smoothing turned on. Some lines required adjustment to the auto bottom tracking delineation, which can be addressed by manually editing the altitude line in SonarWiz. There was a 1-m additional altitude offset applied to the bottom tracking, in order to minimize nadir stripeyness in some parts of the mosaic. The only gain function applied in SonarWiz during shipboard processing was an empirical gain normalization function (EGN) with port and starboard intensities set to 24. Person who carried out this activity:
    Seth Ackerman
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    (508) 548-8700x2315 (voice)
    (508)-457-2310 (FAX)
    sackerman@usgs.gov
    Date: 2014 (process 2 of 5)
    A Beam Angle Correction (BAC) was applied to the data separately from EGN corrections and was noted to reduce stripeyness within the mosaic. However, the dynamic range associated with BAC was less than with the EGN function. Only the EGN-corrected mosaic was exported from SonarWiz since the dynamic range is the most important to mosaic quality. Because the survey area was relatively long from North to South, the mosaic had to be split into 4 separate images in order to export them from SonarWiz version 5.07.0008 at 1-m resolution. Four areas were defined within SonarWiz and images were exported as 8-bit GeoTIFF images, where light tones have high backscatter values and dark tones have low backscatter values. The four GeoTIFF images were opened in ArcMap version 10.2 and mosaicked into one file and a .tfw file was created using the 'export raster world file' tool. Person who carried out this activity:
    Elizabeth Pendleton
    U.S. Geological Survey
    Geologist
    U.S. Geological Survey
    Woods Hole, MA
    USA

    (508)-548-8700x2259 (voice)
    (508)-457-2310 (FAX)
    ependleton@usgs.gov
    Date: 18-Apr-2017 (process 3 of 5)
    The online links to the data were updated to reflect the new server hosting the data. Additionally, other small edits could be made to the metadata, such as modifying http to https where appropriate. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. 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
    Date: 20-Jul-2018 (process 4 of 5)
    USGS Thesaurus keywords added to the keyword section. 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
    Date: 08-Sep-2020 (process 5 of 5)
    Added keywords section with USGS persistent identifier as theme keyword. 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?
  2. How accurate are the geographic locations?
    During Field activity 20014-002-FA, the Klein 3000 was towed from the stern A-frame of the M/V Scarlett Isabella. Differential GPS (DGPS) position data were provided by a Hemisphere DGPS receiver and recorded to the raw data files (XTF) via SonarPro (version 10.0) on the sonar acquisition computer. The GPS antenna was mounted on the port side of the acquisition lab van. All GPS data during this survey were referenced to the WGS84 horizontal datum. The horizontal offsets between the GPS antenna and the sheave on the A-frame were measured prior to the survey (x: +4.4m; y: -12.9m; z: 1.0m). The side-scan tow cable was deployed through a 3PS digital block cable counter attached to the A-frame. Real-time cable-out measurements were transmitted via serial connection to the SonarPro acquisition software, which calculated tow-fish layback. All horizontal offsets were applied in the acquisition software so the navigation recorded in the XTF data reflect the position including the layback offset. The layback calculations do not account for fish motion behind the vessel, which is caused by sea state and vessel speed induced changes in the angle and scope of the tow cable. DGPS positional accuracy is estimated to be within 3-5 m; WAAS enable DGPS is estimated to be less than 3 m. Taking the additional fish motion and cable movement into account, as well as the mosaicking process, the positional accuracy for this dataset is estimated to be within 20 m.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    All of the Klein data collected during field activity 2014-002-FA are included in this mosaic and were processed with SonarWiz version 5.07.0008. Klein data were not collected during the entire survey. While regional seismic-reflection profile lines were being acquired with an S-Boom system between 20140617 and 20140626 the Klein 3000 remained on deck to avoid signal crosstalk and instrument entanglement.
  5. How consistent are the relationships among the observations, including topology?
    These sidescan sonar data were collected at 200 meter line spacing to ensure 100 percent backscatter coverage. The M/V Scarlet Isabella can only survey in water depths greater than 8 meters, so there are some gaps in the mosaics where the vessel had to avoid crossing shallow shoals. These gaps were planned with breaks in tracklines or maneuvers around the shoals. Most of the data were acquired roughly parallel to the orientation of Assateague Island at an average speed of 5 knots.

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:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information.
  1. Who distributes the data set? (Distributor 1 of 1)
    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700x2259 (voice)
    (508) 457-2310 (FAX)
    ependleton@usgs.gov
  2. What's the catalog number I need to order this data set? USGS data release 2014-002-FA backscatter mosaic from the Delmarva Peninsula area (2014-002-FA_SSS.zip). The zip file contains the following a GeoTiff image in BigTIFF format: 2014_002_FA_Klein_1m.tif, which has a TIFF world file, with the same image prefix name and a tfw extension. A browse graphic (Delmarva_SSS.png) and FGDC CSDGM metadata files (2014_002_FA_Klein_1m.xml) in four standard formats are also included in the zip file.
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?
  5. Is there some other way to get the data?
    none
  6. What hardware or software do I need in order to use the data set?
    The image contained in the ZIP file is available as BigTIFF GeoTIFF image with a world file. To utilize these data, the user must have an image viewer, or an image processing or GIS software package capable of importing a BigTIFF image. This image may not open in older GIS software (earlier than version 10.0)

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
Metadata author:
Elizabeth A. Pendleton
U.S. Geological Survey
Geologist
U.S. Geological Survey
Woods Hole, MA
USA

508-548-8700 x2259 (voice)
508-457-2310 (FAX)
ependleton@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/field_activities/2014_002_fa/2014_002_FA_Klein_1m.faq.html>
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