Trackline navigation for Edgetech 4200 sidescan sonar data collected in 2015 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (Esri polyline shapefile, GCS WGS 84).

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Frequently anticipated questions:


What does this data set describe?

Title:
Trackline navigation for Edgetech 4200 sidescan sonar data collected in 2015 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (Esri polyline shapefile, GCS WGS 84).
Abstract:
The Delmarva Peninsula is a 220-kilometer-long headland, spit, and barrier island complex that was significantly affected by Hurricane Sandy in the fall of 2012. The U.S. Geological Survey conducted cruises during the summers of 2014 and 2015 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. Geophysical data collected during the cruises include swath bathymetric, sidescan sonar, chirp and boomer seismic reflection profiles, grab sample and bottom photograph data. 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/, https://cmgds.marine.usgs.gov/fan_info.php?fan=2014-002-FA and https://cmgds.marine.usgs.gov/fan_info.php?fan=2015-001-FA. Data collected during the 2014 survey can be obtained here: https://doi.org/10.5066/F7MW2F60
  1. How might this data set be cited?
    U.S. Geological Survey, 2016, Trackline navigation for Edgetech 4200 sidescan sonar data collected in 2015 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (Esri polyline shapefile, GCS WGS 84).: data release DOI:10.5066/F7P55KK3, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Sweeney, Edward M., Pendleton, Elizabeth A., Ackerman, Seth D., Andrews, Brian D., Baldwin, Wayne E., Danforth, William W., Foster, David S., Thieler, E. Robert, and Brothers, Laura L., 2016, High-resolution geophysical data collected along the Delmarva Peninsula 2015, U.S. Geological Survey Field Activity 2015-001-FA: data release DOI:10.5066/F7P55KK3, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -75.891104
    East_Bounding_Coordinate: -75.310611
    North_Bounding_Coordinate: 37.838720
    South_Bounding_Coordinate: 36.999545
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2015-001-FA/data/backscatter/tracklines/2015-001-FA_ssstracks_browse.jpg (JPEG)
    Thumbnail image of sidescan sonar tracklines for Delmarva Peninsula.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 17-Jun-2015
    Ending_Date: 14-Jul-2015Currentness_Reference:
    ground condition; data were not collected on 20150628 (transition between Legs 1 and 2 of the survey)
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • Entity point (520)
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. 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?
    2015-001-FA_ssstracks
    Sidescan sonar tracklines for survey 2015-001-FA along the Delmarva Peninsula. (Source: U.S. Geological Survey)
    FID
    Internal feature number. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape
    Feature geometry. (Source: Esri) Coordinates defining the features.
    LineName
    Name of the trackline along which sidescan sonar data were collected. Naming convention from Line 40 to 91 uses a format of LineNumber (i.e. 'l40') + FileNumber (i.e. 'f1') + Channels 1 and 2 ('CH-12'). Naming convention from line 92 until the end of the sidescan sonar data set use a format of LineNumber (i.e. 'L150') + Date (YYYYMMDD i.e. '20150708') + UTCTimeAtStartOfLine (HHMMSS i.e. '135305') + Channels 1 and 2 ('CH12'). (Source: U.S. Geological Survey) Character set
    Yr_JD_ini
    Year and Julian date at the start of the survey line in the format: YYYY-JD; where Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set
    JD_UTC_ini
    Julian day and UTC time at the start of the survey line in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set
    Yr_JD_end
    Year and Julian date at the end of the survey line in the format: YYYY-JD; where Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set
    JD_UTC_end
    JulianDay:HH:MM:SS of the end of the survey line in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set
    SurveyID
    WHCMSC field activity identifier (e.g. "2015-001-FA" where 2015 is the survey year, 001 is survey number of that year, and FA is Field Activity). (Source: U.S. Geological Survey) Character set
    VehicleID
    Survey vessel name. (Source: U.S. Geological Survey) Character set
    DeviceID
    Sonar device used to collect sidescan sonar data. (Source: U.S. Geological Survey) Character set
    Length_km
    Length of sidescan sonar data line in kilometers (UTM Zone 18N, WGS84). (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.016
    Maximum:32.112
    Units:kilometers
    Resolution:0.001

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Edward M. Sweeney
    U.S. Geological Survey
    Physical Scientist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2256 (voice)
    508-457-2310 (FAX)
    emsweeney@usgs.gov

Why was the data set created?

This dataset contains trackline navigation for approximately 4,080 km of Edgetech sidescan sonar data collected by the U.S. Geological Survey during cruise 2015-001-FA along the Delmarva Peninsula, MD and VA. This information can help spatially correlate the sidescan sonar mosaic with other data in the GIS.

How was the data set created?

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

    Type_of_Source_Media: disc
    Source_Contribution:
    Sidescan sonar data were collected with an Edgetech 4200 dual frequency (100/410 kHz) frequency modulated sidescan-sonar towfish on the M/V Scarlet Isabella. 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 Edgetech Discover (version 34.0.1.106) acquisition software (lines L40F1 to L47F1) and SonarWiz software (version 6.01.0009) (lines L47F3 to L183-20150714_134804) on the sonar acquisition computer for layback calculation. Tracklines are generally spaced 200 m apart.
  2. How were the data generated, processed, and modified?
    Date: 2015 (process 1 of 4)
    Navigation was exported from SonarWiz (version 6.01.0009) as a CSV (Comma Separated Value) text file by selecting TOOLS and EXTRACT CSF (Chesapeake Sonar File) NAVIGATION TO TEXT FILE. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Wayne Baldwin
    Physical Scientist
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
    Date: 14-Jul-2015 (process 2 of 4)
    Python and shell scripts were used to reformat the navigation text files and add them to a geospatial SQLite (version 3.7.9) database. The processing flow for this step follows:
    A. A Python script (pyReformatSidescanNav.py) was used to read and reformat CSV navigation files. The script reformatted each record to include the Julian Day (JD) with year and time, and it added fields for the survey line name, field activity number (2015-001-FA), survey vessel (M/V Scarlett Isabella) and the device used (Edgetech 4200).
    B. A Python script (pySQLBSidescanNav.py) ran on each reformatted CSV file, parsing the file from each record and adding points to an SQLite database (which is created if it does not already exist). The pySQLSidescanNav script creates both point and trackline navigation for each survey line. This process populates attribute fields for the survey line ('LineName'), Year and Julian day ('Year_JD_init') survey line started, Julian day and UTC time ('JD_UTC_init') survey line started, Year and Julian day ('Year_JD_end') survey line ended, Julian day and UTC time ('JD_UTC_end') survey line ended, survey ID ('SurveyID'), survey vessel name ('VehicleID'), device used to collect the data ('DeviceID') and length field ('Length_km').
    C. When all of the survey lines have been processed into SQLite database, a polyline shapefile is exported from the database using the spatialite_tool command (Spatialite version 3.0.1). Steps A and B were both run within a shell script called sonarwiznavconv. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Wayne Baldwin
    Physical Scientist
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
    Date: 18-Feb-2016 (process 3 of 4)
    XTools Pro (version 12.0) for ArcGIS desktop (version 10.3) was used (TABLE OPERATIONS - TABLE RESTRUCTURE) to rename long attribute headings in the polyline shapefile's attribute table. Table attributes for the survey line ('LineName' remained the same), Year and Julian day ('Year_JD_init' was changed to 'Yr_JD_ini') survey line started, Julian day and UTC time ('JD_UTC_init' was changed to 'JD_UTC_ini') survey line started, Year and Julian day that the survey line ended ('Year_JD_end' was changed to 'Yr_JD_end'), Julian day and UTC time that the survey line ended ('JD_UTC_end' remained the same), survey ID ('SurveyID' remained the same), survey vessel name ('VehicleID' remained the same), device used to collect the data ('DeviceID' remained the same) and length field ('Length_km' remained the same). Person who carried out this activity:
    U.S. Geological Survey
    Attn: Edward M. Sweeney
    Physical Scientist
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2256 (voice)
    508-457-2310 (FAX)
    emsweeney@usgs.gov
    Date: 19-Apr-2017 (process 4 of 4)
    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
  3. What similar or related data should the user be aware of?
    Pendleton, Elizabeth A., Ackerman, Seth D., Baldwin, Wayne E., Danforth, William W., Foster, David S., Thieler, E. Robert, and Brothers, Laura 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:


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 2015-001-FA, the Edgetech 4200 was towed from the stern A-frame of the M/V Scarlett Isabella. Position data were acquired using a Wide Area Augmentation System (WAAS) enabled Hemisphere Differential Global Positioning System (DGPS) receiver. Horizontal position solutions were recorded to the raw data files (JSF and XTF) via Edgetech Discover (version 34.0.1.106) acquisition software (lines L40F1 to L47F1) and SonarWiz software (version 6.01.0009) (lines L47F3 to L183-20150714_134804) on the sonar acquisition computer. The GPS antenna was mounted on the forward port side of the acquisition lab van. All GPS data during this survey were referenced to the WGS 84 horizontal datum. The horizontal offsets between the GPS antenna and the sheave on the A-frame were measured prior to the survey (x: +3.76 m; y: -12.76 m; z: 1.0 m). 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 Discover and SonarWiz acquisition software, which calculated tow-fish layback. All horizontal offsets were applied in the acquisition software so the navigation recorded in the JSF and 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 horizontal positional accuracy is estimated to be within 3-5 m; WAAS enable GPS is estimated to be within 2 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 Edgetech navigation data collected during field activity 2015-001-FA are included in this shapefile and were processed with SonarWiz (version 6.01.0009). Edgetech data were not collected during the entire survey. While regional seismic-reflection profile lines were being acquired with an S-Boom system between 20150610 and 20150618 and during bottom sampling between 20150714 and 20150716, the Edgetech 4200 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. Most of the 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. Line numbering in the sidescan sonar data begins with L40F1, which corresponds to the survey line where sidescan data collection began after the multi-channel seismic reflection profiling survey.

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 as the originator of the dataset.
  1. Who distributes the data set? (Distributor 1 of 1)
    Edward M. Sweeney
    U.S. Geological Survey
    Physical Scientist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2256 (voice)
    508-457-2310 (FAX)
    emsweeney@usgs.gov
  2. What's the catalog number I need to order this data set? USGS data release 2015-001-FA sidescan sonar trackline data from the Delmarva Peninsula area (2015-001-FA_ssstracks.zip). The zip file contains a folder with the following shapefile: 2015-001-FA_ssstracks.shp, a browse graphic (2015-001-FA_ssstracks_browse.jpg) and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata files (2015-001-FA_ssstracks.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. What hardware or software do I need in order to use the data set?
    This zip file contains data available shapefile format. The user must have software capable of reading shapefile format to use these data.

Who wrote the metadata?

Dates:
Last modified: 19-Apr-2017
Metadata author:
Edward M. Sweeney
U.S. Geological Survey
Physical Scientist
384 Woods Hole Road
Woods Hole, Massachusetts
USA

508-548-8700 x2256 (voice)
508-457-2310 (FAX)
emsweeney@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.36 on Wed Apr 19 13:04:51 2017