SONAR_TRKNAV.SHP: Sidescan-sonar trackline navigation collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, MA, 2007. (ESRI POLYLINE SHAPEFILE)

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Frequently-anticipated questions:

What does this data set describe?

Title:
SONAR_TRKNAV.SHP: Sidescan-sonar trackline navigation collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, MA, 2007. (ESRI POLYLINE SHAPEFILE)
Abstract:
The USGS Woods Hole Science Center conducted a nearshore geophysical survey offshore of the southern coast of Martha's Vineyard, in the vicinity of the Martha's Vineyard Coastal Observatory (MVCO) in August 2007. This mapping program was part of a larger research effort supporting the Office of Naval Research (ONR) Ripples Directed-Research Initiative (DRI) studies at MVCO by providing data collection and modeling. The geophysical data will be used to provide initial conditions for wave and circulation models for the study area. Ultimately, geophysical mapping, oceanographic measurements and modeling will help to improve our understanding of coastal sediment-transport processes.

The geophysical mapping utilized a suite of high-resolution instrumentation to map the surficial sediment distribution, depth and sub-surface geology: dual-frequency 100/500 KHz sidescan-sonar system, 234-KHz interferometric sonar, and 500 Hz -12 KHz chirp sub-bottom profiler. The survey was conducted aboard the M/V Megan Miller August 9-13, 2007. The study area covers 35 square kilometers from about 0.2 km to 5-km offshore of the south shore of Martha's Vineyard, and ranges in depth from ~ 5 to 20 meters.

  1. How should this data set be cited?

    U.S. Geological Survey, 2009, SONAR_TRKNAV.SHP: Sidescan-sonar trackline navigation collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, MA, 2007. (ESRI POLYLINE SHAPEFILE): Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.

    Online Links:

    This is part of the following larger work.

    Denny, J.F., Danforth, W.W., Foster, D.S., and Sherwood, C.R., 2009, Geophysical Data Collected off the South Shore of Martha's Vineyard, Massachusetts: Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.599937
    East_Bounding_Coordinate: -70.513351
    North_Bounding_Coordinate: 41.346920
    South_Bounding_Coordinate: 41.303623

  3. What does it look like?

    <https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Tracklines/sonar_trknav_sm.jpg> (JPEG)
    Thumbnail image of sidescan-sonar trackline navigation collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, 2007

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 09-Aug-2007
    Ending_Date: 13-Aug-2007
    Currentness_Reference: ground condition

  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):

      • String (98)

    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?

    sonar_trknav
    ESRI polyline shapefile (Source: ESRI)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Line
    Line and file number for corresponding sidescan-sonar files. This information is used during data acquisition, processing and archival. (Source: U.S. Geological Survey)

    L3-Klein Associates naming convention for collected sonar lines of data. The format is: L1F1, where L=line, 1= Number, F=File, 1=File number, _0708= MMDD, and 1200=HHMM

    JD
    Julian Day during which sonar data were collected (Source: U.S. Geological Survey)

    Range of values
    Minimum:221
    Maximum:225
    Units:Julian Day (Year 2007)

    Year
    Calendar year sonar data were collected (Source: U.S. Geological Survey)

    Calendar year USGS cruise 07011 was conducted. (2007)

    System
    Sidescan-sonar system used for data acquisition (Source: U.S. Geological Survey)

    Text field

    Frequency
    Frequency of sidescan-sonar data acqusition system (Source: U.S. Geological Survey)

    Text field

    Swath
    Swath width used during sidescan-sonar data acqusition (meters). (Source: U.S. Geological Survey)

    ValueDefinition
    100 meterswath width of sidescan-sonar system used during data acquisition.

    Cruise_ID
    Unique USGS cruise identification (Source: U.S. Geological Survey)

    ValueDefinition
    07011USGS Cruise Identification Number, where the first two digits represent calendar year and the last three digits represent cruise number

    Length
    length of line segment in UTM, Zone 19N, WGS84, kilometers (Source: U.S. Geological Survey)

    Range of values
    Minimum:0.890747
    Maximum:6.934814
    Units:Kilometers

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?

    U.S. Geological Survey

  3. To whom should users address questions about the data?

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

Why was the data set created?

This dataset contains trackline navigation for approximately 620 km of shore-parallel sidescan-sonar data collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, 2007.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    .

    Source_Contribution:
    Data were acquired with an L3-Klein Associates 3000 digital, dual-frequency, sidescan-sonar (www.l-3klein.com). Dual frequencies are nominally 100 (132 kHz) and 500 (445 kHz) kHz. The sidescan-sonar was towed aft of the R/V Megan Miller. A digital cable-out display was used to measure tow-fish layback. Layback and DGPS input were used by the SonarPro acquisition software to calculate position of the sonar tow-fish and store in the raw data files. Line spacing varied from 40 meter in ~ 5 to 15 meter water depth to 75 meters in ~15 - 25 meter water depth. Data files were recorded with SonarPro 10.0 in XTF (extended-Triton Format) format at a 0.03-sec ping rate yielding a 50-meter range (100-meter swath). The 100 kHz data were used to generate the sidescan-sonar mosaic. The data range within the sidescan-sonar mosaic (digital number values (DN) of the 8-bit image) is 0 - 250, with the background value (i.e. No DATA) set to 255.

  2. How were the data generated, processed, and modified?

    Date: 2008 (process 1 of 5)
    Navigation data were extracted at 1 minute intervals from the raw sidescan sonar data (XTF format) during the 'demultiplex' phase of data processing within XSonar/ShowImage sidescan-sonar processing software (Danforth and others, 1991) and stored in ASCII files. Software: XSonar/ShowImage (no version)

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

    Date: 2008 (process 2 of 5)
    A c-shell script was used to reformat the output from degrees decimal minutes to decimal degrees. Proj (version 4.6.1) and AWK (GNU 3.1.5) were used to convert decimal degrees to eastings and northings (based on UTM Zone 19 N, WGS84) and to reformat the output as a comma delimited ASCII file including headers listing field names (Easting, Northing, Line Number, Julian Day, Hour, Minute, Second, Longitude, Latitude).

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

    Date: 2008 (process 3 of 5)
    The ASCII file (*.csv) was imported into ESRI ArcMap 9.2 using Tools - Add XY Data and converted to an event theme. The event theme was then saved to a point shapefile and the projection was defined as Geographic Coordinate System, WGS84 (GCS_WGS_1984). The point shapefile was visually inspected for spurious data points and these data points were manually deleted.

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

    Date: 2008 (process 4 of 5)
    The point shapefile containing 1-minute navigation was used as an input for VACExtras (version 1.8), a Visual Basic collection of tools developed by VeeAnn Cross (USGS-WHSC), which converts point data to a new polyline shapefile based on the order of records contained within one attribute field. The line number field was used to define the point order.

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

    Date: 2008 (process 5 of 5)
    Julian Day, Year, System, Frequency, Swath, and Cruise_ID fields were added to the attribute table within ArcMap 9.2. The length of each line segment was calculated and included in a new attribute field using XTools Pro for ArcGIS desktop (version 5.3.0), specifying UTM Zone 19 N, WGS84, units kilometers.

    Software: XTools Pro (5.3.0), ArcGIS 9.2

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

  3. What similar or related data should the user be aware of?

    Danforth, W.W., O'Brien, T.F., and Schwab, W.C., 1991, USGS image processing system: near real-time mosaicking of high-resolution sidescan-sonar data: Sea Technology January 1991, Sea Technology, Arlington, VA.

    Danforth, William W. , 1997, XSonar/ShowImage: A complete system for rapid sidescan-sonar processing and display.: Open-File Report 97-686, U.S. Geological Survey, Woods Hole, MA.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    Attributes relay information about the object ID (i.e. polyline), date of data collection, type of sonar system used to acquire data, the frequency of the sonar system, swath width of the sonar system, USGS unique cruise identification, and the length of tracklines (km). Attributes were checked for consistency and for accuracy of descriptive information.

  2. How accurate are the geographic locations?

    Differential Global Positioning System (DGPS) navigation data were acquired with a LGBX Pro receiver and sent directly to the sidescan-sonar acquisition software, L3-Klein Associates, SonarPro. The LGBX Pro received DGPS positions from a DGPS antenna located on the starboard, aft roof of the acquisition van. The layback of the sidescan-sonar towfish was measured with a digital block cable counter. The cable counter data were sent directly to SonarPro as a serial string. SonarPro computes the actual tow-fish position using the DGPS input and the layback. The following offsets are measured prior to deployment of the sidescan-sonar tow-fish and entered into SonarPro: height of the block, offset from DGPS antenna to the block, and height of the DGPS antenna above the waterline. Prior to deploying the sidescan-sonar tow-fish, the tow-fish is hauled to the block in order to zero the cable counter. DGPS accuracy is 1 to 3 meters, depending on the distance from a US Coast Guard coastal repeater station (<http://www.navcen.uscg.gov/>).

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    All available data were used to create the trackline navigation. Sidescan-sonar data were only collected along shore-parallel tracklines; sonar data were not collected along shore-perpendicular tie lines.

  5. How consistent are the relationships among the observations, including topology?

    Trackline navigation were edited during processing in order to remove spurious navigation fixes.

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)

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  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 in Environmental Systems Research Institute (ESRI) polyline shapefile format. The user must have ArcGIS or ArcView 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing the data. A free data viewer, ArcExplorer, capable of displaying the data is available from ESRI at www.esri.com.

Who wrote the metadata?

Dates:
Last modified: 04-Oct-2009
Metadata author:
Jane Denny
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.25 on Sun Oct 04 17:14:41 2009