2-meter Swath interferometric backscatter data collected in 2014 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (8-bit GeoTIFF, UTM Zone 18N, WGS 84)

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Frequently anticipated questions:


What does this data set describe?

Title:
2-meter Swath interferometric backscatter data collected in 2014 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (8-bit 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 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 Woods Hole Coastal and Marine Science Center 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, 2016, 2-meter Swath interferometric backscatter data collected in 2014 by the U.S. Geological Survey along the Delmarva Peninsula, MD and VA (8-bit 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/2014_002_FA_SwathBS_2m_100.png (PNG)
    thumbnail image of SwathPlus backscatter data for the 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; 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 N
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -75
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000.0
      False_Northing: 0.0
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 2
      Ordinates (y-coordinates) are specified to the nearest 2
      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. Pixel values for the GeoTIFF have a possible 8-bit pixel range of 0 to 255. However, the acoustic reflectivity data range from 1 to 53. Low-backscatter is represented by dark tones (low values) and high-backscatter is represented by bright tones (high values). In this TIFF format, the NODATA values are represented as NODATA.
    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?

This 2-m uninterpolated SwathPlus backscatter image was created from swath interferometric data. These data, although they contain small data gaps, are included in addition to side scan sonar data due to the higher positional accuracy of these data when compared to sidescan backscatter. Backscatter data are useful geophysical datasets for geologic framework studies. These data can be used in conjunction with other geophysical and sample data to identifying 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 interferometric data in sxr format.

    Type_of_Source_Media: disc
    Source_Contribution:
    USGS used a 234 kHz Systems Engineering and Assessment Ltd. (SEA) SWATHplus interferometric sonar (now BathySwath) mounted on the port side of the M/V Scarlett Isabella. The motion reference unit was located on the head of the transducer.
    Survey lines were run at an average speed of 5 knots and were spaced 200 m apart in the nearshore. The SEA SWATHplus-M (BathySwath-1) operates at a frequency of 234 kHz and a variable range (increased or decreased manually depending on water depth, but generally 85-100 m on both sides). The system was operated with a transmit power of 80 percent, a transmit length of 43 cycles, and 4096 samples per channel.
  2. How were the data generated, processed, and modified?
    Date: 30-Jul-2014 (process 1 of 5)
    Each raw BathySwath bathymetric sonar file (sxr) was imported into SonarWiz version 6.01.0009 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 4; a duration value of 2; and a threshold of 19 with line smoothing turned on. Some lines required further adjustment to the auto bottom tracking delineation, which can be addressed by manually editing the altitude line in SonarWiz. The only gain function applied in SonarWiz during shipboard processing was an empirical gain normalization function (EGN). The Overlap Mode in the SonarWiz project was set to root mean square (RMS), which displays backscatter data in overlapping areas using an RMS adjustment. 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: 30-Jul-2015 (process 2 of 5)
    The interferometric backscatter mosaic was exported from SonarWiz version 6.01.0026 as an 8-bit GeoTIFF (UTM Zone 18N, WGS 84) at 2-m resolution. High backscatter values are shown by light tones and low backscatter values are shown by dark tones in the imagery. A world file with the same prefix file name and .tfw extension was created in ArcMap version 10.3.1 using 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?
    Navigation was acquired with a Coda Octopus F185 Differential Global Positioning System + Wide Area Augmentation System (DGPS+WAAS), which is accurate to + or - 1 to 2 meters, horizontally and RTK positioning from an Ashtech Proflex 800, which is accurate to less than 1-meter, horizontally. X,Y data are referenced to WGS84. The SWATHPlus transducers were mounted on a rigid pole, approximately 4.195 m below the water line, along the port side of the M/V Scarlett Isabella. The DGPS antenna and an Ashtech ProFlex 800 RTK GPS were located on the same pole approximately 4.6 m above the sea surface. RTCM corrections were being delivered via the web (ethernet) to the Ashtech ProFlex 800 from shore stations in MD and VA (ethernet satellite link is from a KVH Mini-VSAT Broadband receiver). The RTK corrections were passed through to the F185R giving the SWATHplus system kinematic (x,y) positioning accuracy from Julian Day 170 and later. Lines (l1f1-l7f1) collected prior to 20140719 at 12:40:00 UTC were recorded with WAAS-enabled DGPS because the F185 was not receiving RTCM corrections from the Ashtech ProFlex800. Positional offsets from antennae to MRU were corrected within the SWATHPlus acquisition software.
    WAAS enabled DGPS accuracy is estimated to be less than 3 m and the accuracy of RTK-GPS is estimated to be less than 1 m.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Survey line bathymetry data that were collected within the Delmarva survey area were incorporated in this grid with the exception of the lines listed below. These lines were left out of the final mosaic either because the data quality were poor, the lines were duplicated or superseded by another line of better data quality, the line was a jog around a shoal and was redundant, or their contribution to the final product was not significant, such as the widely spaced (3 km) boomer seismic lines. l1f1-f3; l2f1-f5; l3f1-f3; l5f3; l4f1-f4; l5f1-f2; l6f1-f2; l7f1-f5; l8f1-f3; l9f1-f3; l10f1-f5;l11f1-f2; l12f1-f3; l13f1-f3; l12f1-f4; l15f1-f3; l16f1-f2; l17f1-f3; l19f1-l19f8; l20f-l20f8; l21f1-f8; l22f1-f7; l23f1-f8; l23f1-f8; l24f1-f7; l25f1-f2 ;l26f; l27f1-f2; l28f1; l29f1-f2; l30f1-f2; l31f1; l32f1-f2; l33f1; l34f1-f2; l35f1;l36f1-f2; l37f1; l38f1-f2; l39f1; l40f1-f3; l41f1;l42f1-f2; l43f1; l44f1-f2; l50f10; l51f1-l5f4; l52f1-l52f2; l100f1-l100f3; l96f1; l103f3; l155f2; l163f3; and t1f1-t13f1.
  5. How consistent are the relationships among the observations, including topology?
    This image represents uninterpolated swath interferometric backscatter data at 2.0 meter resolution. The swath width of the interferometric sonar is limited by water depth and other oceanographic conditions like changes in the speed of sound due to salinity, temperature, and stratification. 100 percent overlap was not achieved in all areas of the survey. Small data gaps exist due to the limited range of the sonar, and these gaps were left unfilled in the mosaic. Trackline artifacts associated with NADIR and acquisition parameters can also be seen in the mosaic.

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:
Not to be used for navigation. 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 interferometric backscatter from the Delmarva Peninsula area (2014-002-FA_SwathBS.zip). The zip file contains the following a GeoTiff image in BigTIFF format: (2014-002-FA_SwathBS_2m.tif) with a world file (2014-002-FA_SwathBS_2m.tfw). A browse graphic (2014_002_FA_SwathBS_2m_100.png) and FGDC CSDGM metadata files (2014_002_FA_SwathBS_2m.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_SwathBS_2m.faq.html>
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