Trackline navigation for 512i seismic-reflection data collected by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA, 2014 (Esri polyline shapefile, GCS WGS 84)

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Frequently anticipated questions:

What does this data set describe?

Title:
Trackline navigation for 512i seismic-reflection data collected by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA, 2014 (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. 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, Trackline navigation for 512i seismic-reflection data collected by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA, 2014 (Esri polyline shapefile, GCS 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, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Pendleton, Elizabeth 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: -75.567695
    East_Bounding_Coordinate: -74.687529
    North_Bounding_Coordinate: 38.430403
    South_Bounding_Coordinate: 37.538209
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2014-002-FA/data/seismics/tracks/512_tracks.png (PNG)
    Woods Hole Coastal and Marine Science Center 512i tracklines along the Delmarva Peninsula
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 18-Jun-2014
    Ending_Date: 22-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: 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):
      • Complete chain (407)
    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?
    2014_002_FA_512i_Tracklines
    512i tracklines for survey 2014-002-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.
    FileName
    Name of seismic data file. (Source: U.S. Geological Survey) String up to 254 characters
    Image
    name of seismic profile image used as hyperlink (Source: U.S. Geological Survey) String up to 254 characters
    Shot
    First shot number in seismic profile (Source: U.S. Geological Survey)
    Range of values
    Minimum:1
    Maximum:1
    Units:shot
    Resolution:1
    Year
    Calendar year data were collected (Source: U.S. Geological Survey) String up to 254 characters
    Time_UTC
    JulianDay:HH:MM:SS of the start of line. Julian day data were collected (Julian day is the integer number representing the interval of time in days since January 1 of the year) (Source: U.S. Geological Survey) String up to 254 characters
    Shot_end
    Last shot number in seismic profile (Source: U.S. Geological Survey)
    Range of values
    Minimum:407
    Maximum:40509
    Units:shot
    Resolution:1
    Time_U_end
    JulianDay:HH:MM:SS of the end of line. Julian day is the integer number representing the interval of time in days since January 1 of the year. (Source: U.S. Geological Survey) String up to 254 characters
    length_km
    Length of seismic profile in kilometers (UTM Zone 18N, WGS84) (Source: U.S. Geological Survey)
    Range of values
    Minimum:0.215
    Maximum:45.0392
    Units:kilometers
    Resolution:0.001
    Survey_ID
    WHCMSC field activity identifier (e.g. "2014-002-FA" where 2014 is the survey year, 002 is survey number of that year, and FA is Field Activity) (Source: U.S. Geological Survey) Character String
    Device_ID
    Sonar device used to collect seismic-reflection data (Source: U.S. Geological Survey) String up to 254 characters
    Vehicle_ID
    Survey vessel name (Source: U.S. Geological Survey) String up to 254 characters
    Entity_and_Attribute_Overview:
    The PNG seismic reflection images can be hyperlinked to their trackline location in ArcGIS.
    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?
  3. To whom should users address questions about the data?
    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA
    USA

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

Why was the data set created?

This dataset contains trackline navigation for approximately 4500 km of 512i chirp seismic-reflection data collected by the U.S. Geological Survey during cruise 2014-002-FA along the Delmarva Peninsula, MD and VA. This information can help spatially correlate the seismic-reflection profiles with other data in the GIS.

How was the data set created?

  1. From what previous works were the data drawn?
    SEG-Y and JSF 512i data (source 1 of 1)
    U.S. Geological Survey, 2015, 512i navigation.

    Type_of_Source_Media: disc
    Source_Contribution:
    Chirp seismic data were collected using an EdgeTech Geo-Star FSSB sub-bottom profiling system and an SB-0512i towfish (0.5-12 kHz), which was mounted on a catamaran and towed astern of the M/V Scarlett Isabella of Cape May, NJ. Chesapeake Technologies' SonarWiz (v.5.00.0015) seismic acquisition software was used to control the Geo-Star topside unit, digitally log trace data in the SEG-Y Rev. 1 format (IEEE floating point) and JSF format, and record GPS navigation coordinates to the SEG-Y trace headers (in arc seconds of Latitude and Longitude, multiplied by a scalar of 100). Data were acquired using a 250 ms shot rate, a 5-ms pulse length, and a 0.5 to 8 kHz frequency sweep. Recorded trace lengths were approximately 180 ms.
  2. How were the data generated, processed, and modified?
    Date: 2014 (process 1 of 7)
    Scripts within SIOSEIS (version 2010.2.25) and Seismic Unix (version 4.2) were used to process SEG-Y data, create navigation files, and plot images. The processing flow and scripts used to produce layback corrected navigation files including trackline shapefiles and shotpoints are summarized below and in the following processing steps.
    1. SIOSEIS (version 2010.2.25) was used to read SEG-Y files, renumber shots starting from one, and write out new SEG-Y files. The original shot numbers, which were assigned by SonarWiz sequentially over the duration of an acquisition session despite SEG-Y file changes, are preserved in the raw SEG-Y data. 2. Sio_medianstk was used to remove S-boom cross talk (when multi-channel streamer lines were recorded simultaneously: Julian Day 169-178) with a two-trace median stack and improve water bottom picking. This script was used for all lines even after multi-channel streamer was turned off, due to the improvements made to water bottom picks. 3. Read512i_mstk was used to read median filtered stacked and renumbered SEG-Y files, write a Seismic Unix file, and extract SEG-Y trace header information, including shot number, longitude, latitude, year, Julian day, and time of day (UTC). Header information from each SEG-Y file was saved to text files after an AWK (no version) filter was used to maintain the first and last shots, shots at multiples of 100, and shots with unique navigation coordinates. Geographic coordinates (WGS84) were converted to UTM zone 18 coordinates (WGS84) using Proj (version 4.6.0). End shots and shots at multiples of 100 may not have unique navigation coordinates. Separate text files containing the first and last shots and even 500 shot intervals were also saved. A 500 shot interval was chosen because it corresponds to the annotation interval provided along the top of the seismic-reflection profile images, which are included in the folders within 'seis_images\512i'. Person who carried out this activity:
    Dave Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700x2271 (voice)
    (508) 457-2310 (FAX)
    dfoster@usgs.gov
    Date: 2014 (process 2 of 7)
    A Python (version 2.7) script was used to apply layback to seismic navigation acquired during the 2014-002-FA survey. Attributes oldEast and oldNorth in the table ‘2014_002_512i_lbunique.csv', which is included in the zip compressed version of the shapefile ‘2014-002-FA_512i_500sht.shp', document pre-layback shot/trace positions. Using Easting and Northing coordinates (UTM Zone 18 N, WGS84) from the trace headers, the script calculated easting and northing differential values between consecutive trace positions. Headings between consecutive traces were calculated using the arctangent function (arctan2(dy,dx)), and reciprocal back bearings were determined using a lookup table. Back bearings were smoothed along track using a moving median function with a window length defined by the user (59 traces during 2014-002-FA ). Layback easting and northing offsets were calculated by multiplying the linear distance between the catamaran and the shipboard DGPS receiver (33 for line 1 or 43 m for all other lines during 2014-002-FA) by the sine and cosine of the smoothed back bearing, respectively. Offset values were then added to the original coordinates to produce layback positions. Person who carried out this activity:
    Dave Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700x2271 (voice)
    (508) 457-2310 (FAX)
    dfoster@usgs.gov
    Date: 2014 (process 3 of 7)
    An awk (do_nav_gisprep) script was used to process unique, 100 shot, and 500 shot lay-back corrected navigation to a merged csv file that can be utilized by ArcGIS to create a trackline and shotpoint shapefile.
    Text files containing unique shot point positions for each seismic line with layback-adjusted navigation were concatenated into a comma-delimited text file. Then the layback-corrected position CSV file was imported into ArcMap (version 10.2.2) using 'Add XY data' and saved as points (Geographic, WGS84) in the Esri shapefile format. Person who carried out this activity:
    Dave Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700x2271 (voice)
    (508) 457-2310 (FAX)
    dfoster@usgs.gov
    Date: 2014 (process 4 of 7)
    The shapefile containing unique shot point positions, created in the previous step, was used as an input for VACExtras points to lines (version 2.1), a VB collection of tools developed by VeeAnn Cross (USGS-WHCMSC), which converts point data to a new polyline shapefile ('2014_002_FA_512i_Tracklines.shp'), based on record order. The 'FileName' field was used to define which points were used to generate each polyline feature. The length of each polyline segment was calculated and included in the attribute field 'Length_km', specifying UTM, Zone 18 N, WGS84, and kilometers with ArcMap version 10.2.2. Additional fields for vessel name, device and survey ID were added in ArcMap Person who carried out this activity:
    Dave Foster
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA
    USA

    (508) 548-8700x2271 (voice)
    508-457-2310 (FAX)
    dfoster@usgs.gov
    Date: 19-Apr-2017 (process 5 of 7)
    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 6 of 7)
    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 7 of 7)
    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?
    Differential Global Positioning System (DGPS) navigation data were acquired with a Hemisphere receiver and recorded with HYPACK (www.hypack.com). The DGPS antenna was located on the port-side of the acquisition van. The SB-0512i was mounted on a catamaran sled and towed at the sea surface approximately 43 m astern of the M/V Scarlett Isabella. Fish depth below water line was 0.5 meters below catamaran floats. The GPS offset from sheave was x = 8.75 m; y = -43 m; z = 0. Navigation data were sent to SonarWiz (version 5) acquisition application and offsets were recorded in the acquisitions software, which logged the coordinates to individual trace headers SEG-Y and JSF format. Positional accuracy is assumed to be better than 10 m and is primarily related to changes in cable-out related to fish and sled motion behind the boat.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Sections of tracklines where navigation was recorded but no seismic data were logged are not included such as turns and transits.
  5. How consistent are the relationships among the observations, including topology?
    Any spurious data points were removed during processing. For each seismic trackline there is one seismic-profile image that is hyperlinked by the field 'image'. No duplicates exist.

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)
    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 512i tracklines from the Delmarva Peninsula area (2014-002-FA_512tracks.zip). The zip file contains a folder with the following a shapefile with 512i trackline locations (2014_002_FA_512i_Tracklines.shp), a browse graphic (512_tracks.png), and FGDC CSDGM metadata files (2014_002_FA_512i_Tracklines.xml) in four standard formats.
  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 shapefile format. The user must have software capable of reading and processing the data file.

Who wrote the metadata?

Dates:
Last modified: 18-Mar-2024
Metadata author:
Elizabeth Pendleton
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA

(508) 548-8700x2259 (voice)
(508) 457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240318)
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_512i_Tracklines.faq.html>
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