50-meter grid representing the Holocene transgressive surface (in meters) beneath the inner-continental shelf offshore of Fire Island, NY (FI_HTS, UTM Zone 18N, WGS 84, Esri Binary Grid)

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Frequently anticipated questions:

What does this data set describe?

Title:
50-meter grid representing the Holocene transgressive surface (in meters) beneath the inner-continental shelf offshore of Fire Island, NY (FI_HTS, UTM Zone 18N, WGS 84, Esri Binary Grid)
Abstract:
The U.S. Geological Survey (USGS) mapped approximately 336 square kilometers of the lower shoreface and inner-continental shelf offshore of Fire Island, New York in 2011 using interferometric sonar and high-resolution chirp seismic-reflection systems. This report presents maps of bathymetry, acoustic backscatter, the coastal plain unconformity, the Holocene marine transgressive surface and modern sediment thickness. These spatial data support research on the Quaternary evolution of the Fire Island coastal system and provide baseline information for research on coastal processes along southern Long Island. More information about this field activity and the data collected can be found at the Field Activity Web Page (http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2011-005-FA)
  1. How might this data set be cited?
    U.S. Geological Survey, 2014, 50-meter grid representing the Holocene transgressive surface (in meters) beneath the inner-continental shelf offshore of Fire Island, NY (FI_HTS, UTM Zone 18N, WGS 84, Esri Binary Grid): Open-File Report 2014-1203, 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.

    Schwab, William C., Denny, Jane F., and Baldwin, Wayne E., 2014, Maps Showing Bathymetry and Modern Sediment Thickness on the Inner- Continental Shelf Offshore of Fire Island, New York: pre-Hurricane Sandy: Open-File Report 2014-1203, U.S. Geological Survey, Coastal and Marine Geology Program, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -73.279633
    East_Bounding_Coordinate: -72.744588
    North_Bounding_Coordinate: 40.758522
    South_Bounding_Coordinate: 40.545940
  3. What does it look like?
    http://pubs.usgs.gov/of/2014/1203/data/GIS/grids/seismic/fi_hts.jpg (JPEG)
    Depth-colored image of the elevation of the Holocene transgressive surface (NAVD88) beneath the inner-continental shelf offshore of Fire Island, NY
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 21-May-2011
    Ending_Date: 05-Jun-2011
    Currentness_Reference:
    ground condition during 20110522 - 20110605
  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 452 x 895 x 1, type Grid Cell
    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: 0.999600
      Longitude_of_Central_Meridian: -75.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 50.000000
      Ordinates (y-coordinates) are specified to the nearest 50.000000
      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.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: North American Vertical Datum of 1988 (NAVD88)
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    Value
    Elevation (in meters) of the Holocene transgressive surface beneath the inner-continental shelf offshore of Fire Island, NY. (Source: U.S. Geological Survey)
    Entity_and_Attribute_Overview:
    Elevation of the Holocene transgressive surface in Esri grid format. Data values represent the elevation of the Holocene transgressive surface beneath the inner-continental shelf offshore of Fire Island, NY.
    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?
    Jane F. Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x 2311 (voice)
    508-457-2310 (FAX)
    jdenny@usgs.gov

Why was the data set created?

This data set contains a grid representing the elevation (NAVD88) of the Holocene transgressive surface beneath the inner continental shelf offshore of Fire Island, New York. Approximately 2200 line kilometers of chirp sub-bottom data collected with an EdgeTech Geo-Star FSSB sub-bottom profiling system and an SB-0512i towfish (0.5-12 kHz) during USGS survey 2011-005-FA, were analyzed to produce this surface. The Holocene transgressive surface is used in assessing relationships between geologic framework, sea-bed morphology, and sediment textural trends.

How was the data set created?

  1. From what previous works were the data drawn?
    none (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, Chirp seismic-reflection data.

    Type_of_Source_Media: online
    Source_Contribution:
    Shallow geologic framework and surficial geology were interpreted from approximately 2200 trackline kilometers of chirp seismic-reflection profiles that were collected during U.S. Geological Survey field activity 2011-005-FA (http://woodshole.er.usgs.gov/operations/ia/public_ds_info.php?fa=2011-005-FA). Final, post-processed profiles were used to make the interpretations. Survey: Survey lines were run at an average speed of 5 knots. Lines 14 through 27 were run at a 75-m line spacing to achieve full coverage of the seafloor with sonar systems in a priority area of interest in the nearshore, in water depths less than 15 meters. Lines 28 through 92 were run at a 150-m line spacing, with the exception of tie lines (lines 52 through 60, 65 through 67, 89 through 92), which were run at approximately a 2-km line spacing. Seismic Data: 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. Chesapeake Technologies' SonarWiz (v.5.03.0016) 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 record DGPS 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 0.25-s shot rate, a 5-ms pulse length, and a 0.5 to 8 kHz frequency sweep. Recorded trace lengths were approximately 200 ms (4340 samples/trace and .000046-s sample interval).
  2. How were the data generated, processed, and modified?
    Date: 2013 (process 1 of 11)
    Processing Seismic Data: 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. Wayne E. Baldwin performed this and all subsequent process steps. Person who carried out this activity:
    Wayne E. Baldwin
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x 2226 (voice)
    508-457-2311 (FAX)
    wbaldwin@usgs.gov
    Date: 2013 (process 2 of 11)
    Processing SEG-Y: Seismic Unix (version 4.2) was used to read 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.
    Date: 2013 (process 3 of 11)
    Applying Layback to Unique Navigation: An AWK (no version) script was used to apply layback to seismic navigation. The script utilized a read-and-do loop to calculate and apply layback offsets to trace positions. During the initial loop through the script: 1) Easting and northing coordinates (UTM Zone 18, WGS84) for the first five traces of input navigation were read and easting and northing differentials between the consecutive positions were calculated; 2) The signs (+/-) of the differential values were compared to a look-up table to determine the appropriate conversion of the arc tangent (atan2(dy,dx)) angle between consecutive positions to a polar azimuth; 3) The average of the polar azimuths was calculated; 4) The sine and cosine of the average azimuth was calculated and multiplied by the linear distance between the catamaran and the shipboard DGPS receiver (51.5m lines l14f1- l74f1; 43.2m lines l75f1 - ll92f1), providing absolute values for easting and northing offsets, respectively; 5) A look-up table was used to determine the quadrant of the average azimuth and appropriately add or subtract the calculated offsets to the easting and northing coordinates of the first three input traces, producing final layback positions for those traces; 6) Layback and original easting and northing coordinates for the three adjusted traces were printed to a new layback navigation file that also retained additional attributes input records; and 7) Easting and northing coordinates of the fourth and fifth traces, the three azimuths computed between traces two, three, four, and five, and the average azimuth were held as input for calculations conducted in the subsequent loop. During subsequent loops through the script: 1) Easting and northing coordinates for three additional traces from input navigation were read, and easting and northing differentials were calculated between the consecutive positions, including the last trace position held from the previous loop; 2) Three new polar azimuths were calculated using the differential values, then a new average azimuth was calculated from the three that were held, the new three, and the average held from the previous loop (the previously calculated average was factored into the new average to smooth "kinks" along the layback navigation that can result from significantly different average azimuths calculated from one loop to the next); 3) new layback offset values were computed, and applied to the easting and northing coordinates of the last two traces input during the previous loop, and the first trace input during the present loop; 4) layback and original easting and northing coordinates for the three adjusted traces were appended to the layback navigation file started in the previous loop; and 5) easting and northing coordinates of the second and third traces, the three new azimuths, and the average azimuth from the present loop were held as input for calculations conducted in the subsequent loop. Near the end of the input navigation file: 1) if less than three traces were present during a new loop, the layback offsets calculated during the previous loop were applied to remaining trace coordinates; 2) layback and original easting and northing coordinates for the remaining adjusted traces were appended to the layback navigation file; and 3) the script reached its end, closed, and saved the layback navigation file. In this fashion, the script approximated a moving window, in which the average of six trace-to-trace azimuths was used to calculate layback offsets for three central trace positions. Exceptions were at the start of a file, where the first three input trace positions were adjusted using offsets calculated from the average of only four azimuths, and possibly at the end of a file, where remaining traces may have been adjusted using the offsets calculated during the previous loop.
    Date: 2013 (process 4 of 11)
    Text files containing unique shot point positions for each seismic line were concatenated into a comma-delimited text file. Unique navigation (containing shot, x, y, and line number) and SEG-Y files were used as input to LandMark SeisWorksTM 2D (R5000) seismic interpretation software.
    Date: 2013 (process 5 of 11)
    CHIRP seismic reflection data were interpreted using Landmark SeisWorks 2D (R5000) seismic interpretation software. Interpretation consisted of identifying and digitizing erosional unconformities defining the boundaries between Holocene, Pleistocene, and pre-Quaternary seismic units. An isochron representing the two-way travel time between the Holocene transgressive unconformity and seafloor horizon was computed, then sampled at a 20-meter along track interval and exported from SeisWorks as ASCII text. Awk (no version) was used to convert two-way travel times to thicknesses in meters using a constant seismic velocity of 1500 m/s.
    Date: 2014 (process 6 of 11)
    Mass points representing the isopach computed in the previous step were imported into ArcMap (9.3.1) as point features (easting, northing, thickness) using the 'Add XY data' function, then saved as a point shapefile. Using the ArcMap (9.3.1) Spatial Analyst tool Extract Values to Points, with the isopach point shapefile and the regional bathymetry DEM (fi_bathygrid ) as inputs, bathymetric values were extracted at locations coincident with each isopach point and added to the point shapefile attribute table. A new attribute field representing the NAVD88 elevation of the transgressive unconformity was calculated by subtracting the isopach values from the corresponding depths.
    Date: 2014 (process 7 of 11)
    The ArcMap (9.3.1) Spatial Analyst tool 'Topo to Raster' was used to create an interpolated grid of the transgressive unconformity with a 50 meter cell size. Inputs for Topo to Raster consisted of the point shapefile containing the NAVD88 elevations of the transgressive unconformity calculated in the previous step (mass points), and a polygon shapefile traced around the input mass-points (boundary). (No drainage enforcement was used).
    Date: 04-Mar-2016 (process 8 of 11)
    Edits to the metadata were made to fix any errors that MP v 2.9.30 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). All of the online links to the publication pages and data had to be fixed. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 9 of 11)
    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: 18-Nov-2019 (process 10 of 11)
    Crossref DOI link was added as the first link in the metadata. 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 11 of 11)
    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?
    Schwab, William C., Baldwin, Wayne E., Hapke, Cheryl J., Lentz, Erika E., Gayes, Paul T., Denny, Jane F., List, Jeffrey H., and Warner, John C., 2013, Geologic Evidence for Onshore Sediment Transport from the Inner Continental Shelf: Fire Island, New York: Journal of Coastal Research Volume 29, Issue 3, pp. 526-544., Coastal Education and Research Foundation, Inc., Florida, USA.

    Online Links:

    Foster, David S., Swift, Ann B., and Schwab, William C., 1999, Stratigraphic Framework Maps of the nearshore area of southern Long Island from Fire Island to Montauk Point, NY: Open-File Report 99-559, U.S. Geological Survey, Reston, VA.

    Online Links:

    Schwab, William C., Thieler, E. Robert, Denny, Jane F., Danforth, William W., and Hill, Jenna C., 2000, Seafloor sediment distribution off southern Long Island, New York: Open-File Report 00-243, 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?
    The nominal resolution of the chirp seismic-reflection system is 0.5 meter. The vertical resolution of the bathymetric grid (fi_bathygrd) used in generating the transgressive surface elevation is +/- 0.5 m (referenced to NAVD88). Due to system resolution, input data resolution, and survey line spacing (75 meters and 150 meters), overall vertical accuracy is assumed to be on the order of +/- 1 to 2 meters.
  2. How accurate are the geographic locations?
    The Edgetech SB-0512i was mounted on a catamaran sled and towed at the sea surface 51.5 m (lines l14f1 - l74f1) and 43.2 m (lines l75f1 - l92f1) astern of the M/V Scarlett Isabella. Position data were provided by a Differential Global Positioning System (DGPS) navigation receiver (F180 (lines l14f1 - l74f1) and BR2G (lines l75f1 - l92f1)). Layback navigation was generated to account for towfish position. Positional accuracy is assumed to be ± 10 m.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    All chirp seismic reflection data collected during USGS Woods Hole Coastal and Marine Science Center field activity 2011-05-FA were used to interpret stratigraphic units and unconformities (Lines 14 - 92).
  5. How consistent are the relationships among the observations, including topology?
    Chirp seismic-reflection data used to interpret regional geologic framework were collected during USGS Woods Hole Coastal and Marine Science Center field activity 2011-005-FA. The geologic framework interpretations in this report were correlated with previous interpretations by Schwab and others (2000) and Foster and others (1999) for the inner-continental shelf offshore of Fire Island, NY.

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 F. Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x 2311 (voice)
    508-457-2311 (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?
    • Availability in digital form:
      Data format: WinZip file (version 14.0) contains three Esri grids (and associated metadata) that define the Holocene sediment thickness (in meters, fi_hiso), the elevation of the Holocene transgressive surface (NAVD88, fi_hts), and the elevation of the coastal plain unconformity beneath the inner-continental shelf offshore of Fire Island, NY (NAVD88, fi_cpun). The zip file also contains layer files (.lyr) to aid in display of the data within ArcGIS. in format AIG (version ArcGIS 9.3.1) Esri Raster GRID format Size: 1.6
      Network links: http://pubs.usgs.gov/of/2014/1203/data/GIS/grids/fi_seismic.zip
      http://pubs.usgs.gov/of/2014/1203/ofr2014-1203-data_catalog.html
    • Cost to order the data: none

  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?
    These data are available as a ArcInfo 32-bit floating point binary grid in Esri format. The floating point binary grid and associated 'info' folder are stored in one folder 'seismic' that has been compressed using WinZip (ver. 14.0) software. To utilize these data, the user must have software capable of uncompressing the zip file and importing and viewing an Esri ArcRaster grid. The zip file also contains associated metadata.

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
Metadata author:
Jane F. Denny
U.S. Geological Survey
Geologist
394 Woods Hole Road
Woods Hole, Massachusetts
USA

508-548-8700 x 2311 (voice)
508-457-2311 (FAX)
jdenny@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/open_file_report/ofr2014-1203/fi_hts.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:20:40 2021