Interferometric Swath Bathymetry XYZ Data Collected in 2013 from the Chandeleur Islands, Louisiana U.S. Geological Survey (USGS) Field Activity Numbers (FAN) 13BIM02 and 13BIM07.

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Frequently anticipated questions:

What does this data set describe?

Title:
Interferometric Swath Bathymetry XYZ Data Collected in 2013 from the Chandeleur Islands, Louisiana U.S. Geological Survey (USGS) Field Activity Numbers (FAN) 13BIM02 and 13BIM07.
Abstract:
As part of the Barrier Island Evolution Research Project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted nearshore geophysical surveys around the northern Chandeleur Islands, Louisiana, in July and August of 2013. The objective of the study is to better understand barrier-island geomorphic evolution, particularly storm-related depositional and erosional processes that shape the islands over annual to interannual timescales (1‒5 years). Collecting geophysical data will allow us to identify relationships between the geologic history of the island and its present day morphology and sediment distribution. This mapping effort was the third in a series of three planned surveys in this area. High resolution geophysical data collected in each of three consecutive years along this rapidly changing barrier island system will provide a unique time-series dataset that will significantly further the analyses and geomorphological interpretations of this and other coastal systems, improving our understanding of coastal response and evolution over short time scales (1‒5 years). This data series includes the geophysical data that were collected during two cruises (USGS Field Activity Numbers (FAN) 13BIM02, 13BIM03, and 13BIM04, in July 2013; and FANs 13BIM07 and 13BIM08 in August 2013) aboard the R/V Sallenger, the R/V Jabba Jaw, and the R/V Shark along the northern portion of the Chandeleur Islands, Breton National Wildlife Refuge, Louisiana. Primary data were acquired with the following equipment: (1) a Systems Engineering and Assessment, Ltd., SWATHplus interferometric sonar (468 kilohertz [kHz]), (2) an EdgeTech 424 (424 kHz) chirp sub-bottom profiling system, and (3) two Teledyne Odom Hydrographic Systems, Incorporated, Echotrach CV100 single beam echosounders.
This data series report serves as an archive of processed interferometric swath and single-beam bathymetry data. Geographic information system data products include an interpolated digital elevation model, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee metadata.
Note: These data are scientific in nature and are not to be used for navigation purposes. Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Supplemental_Information:
The swath bathymetry data were acquired and processed in the WGS84(G1674) reference frame which is equivalent to the International Terrestrial Reference Frame 2008 (ITRF08). This dataset was subsequently transformed using National Oceanic and Atmospheric Administration (NOAA) VDatum version 3.3 transformation software (http://vdatum.noaa.gov/). The data were transformed from ITRF2008 horizontally to NAD83 (CORS96) and then vertically to NAVD88 relative to the GEOID09 model. The final NAD83, NAVD88 x,y,z position data from each swath survey were merged to generate a digital elevation model with a cell-size resolution of 50 meters, which can be downloaded from https://doi.org/10.3133/ds1032/ds-data-downloads.html.
  1. How might this data set be cited?
    U.S. Geological Survey, 2017, Interferometric Swath Bathymetry XYZ Data Collected in 2013 from the Chandeleur Islands, Louisiana U.S. Geological Survey (USGS) Field Activity Numbers (FAN) 13BIM02 and 13BIM07.:.

    Online Links:

    This is part of the following larger work.

    DeWitt, Nancy T., Miselis, Jennifer L., Fredericks, Jake J., Bernier, Julie C., Reynolds, B.J., Kelso, Kyle W., Thompson, Dave M., Flocks, James G., and Wiese, Dana S., 2017, Coastal Bathymetry Data Collected in 2013 from the Chandeleur Islands, Louisiana: U.S. Geological Survey Data Series 1032, U.S. Geological Survey, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.916275
    East_Bounding_Coordinate: -88.796805
    North_Bounding_Coordinate: 30.097320
    South_Bounding_Coordinate: 29.950588
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2013
    Currentness_Reference:
    data collection interval
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: ASCII digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
  7. How does the data set describe geographic features?
    13BIM02_07_IFB_ITRF08.txt
    ASCII text file containing the processed 5-meter resolution interferometric swath bathymetry x,y,z samples exported from CARIS HIPS and SIPS version 8.1.7 in the acquisition datum of ITRF08. (Source: USGS)
    13BIM02_07_IFB_NAD83_NAVD88_GEOID09.txt
    ASCII text file containing the processed 5-meter resolution interferometric swath bathymetry x,y,z samples exported from CARIS HIPS and SIPS version 8.1.7 (13BIM02_07_IFB_ITRF08.txt) and transformed using VDatum version 3.3 into NAD83 and NAVD88 (orthometric height), derived using the GEOID09 model. (Source: USGS)
    13BIM02_07_IFB_NAD83_MLLW.txt
    ASCII text file 13BIM02_07_IFB_NAD83_NAVD88_GEOID09.txt in which only the vertical component (orthometric height) was transformed from NAVD88 to MLLW using VDatum version 3.3. (Source: USGS)
    ITRF08_X
    X-coordinate (easting) in the datum of ITRF08, of the sample point, in meters (Source: CARIS version 8.7.1) 13BIM02_07_IFB_ITRF08.txt = Minimum - Maximum = 315340 - 326605
    ITRF08_Y
    Y-coordinate (northing) in the datum of ITRF08, of the sample point, in meters (Source: CARIS version 8.7.1) 13BIM02_07_IFB_ITRF08.txt = Minimum - Maximum = 3314850 to 3330935
    Ellipsoid
    Z-coordinate in ellipsoid height in the datum of ITRF08, of the sample point, in meters. (Source: CARIS version 8.7.1) 13BIM02_07_IFB_ITRF08.txt = Minimum - Maximum = -43.856 to -29.575
    Std_Dev
    The standard deviation of the BASE surface value, in meters (Source: CARIS version 8.7.1) 13BIM02_07_IFB_ITRF08.txt = Minimum - Maximum = 0.00 to 0.161
    NAD83_X
    NAD83 X-coordinate (easting) of sample point, in meters (Source: VDatum version 3.3) 13BIM02_07_IFB_NAD83_NAVD88_GEOID09.txt = Minimum - Maximum = 315340.7616 to 326605.7584 13BIM02_07_IFB_NAD83_MLLW.txt = Minimum - Maximum = 315340.7616 to 326605.7584
    NAD83_Y
    NAD83 Y-coordinate (northing) of sample point, in meters (Source: VDatum version 3.3) 13BIM02_07_IFB_NAD83_NAVD88_GEOID09.txt = Minimum - Maximum = 3314849.380 to 3330934.377 13BIM02_07_IFB_NAD83_MLLW.txt = Minimum - Maximum =3314849.38 to 3330934.377
    NAVD88_G09
    The Z-Coordinate in orthometric height (NAVD88) of the sample with respect to GEOID09, in meters (Source: VDatum version 3.3) 13BIM02_07_IFB_NAD83_NAVD88_GEOID09.txt = Minimum - Maximum = -15.38 to -1.35
    MLLW DataType
    The Z-Coordinate as tidal datum (MLLW) of the sample, in meters. (Source: VDatum version 3.3) 13BIM02_07_IFB_NAD83_MLLW.txt = Minimum - Maximum = -15.30 to -1.30

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, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center
  3. To whom should users address questions about the data?
    Nancy T. DeWitt
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov

Why was the data set created?

This zip archive contains processed x,y,z data points for the interferometric swath bathymetry data collected in July 2013 (13BIM02) and August (13BIM07) around the Chandeleur Islands, Louisiana.
NOTE: These data are scientific in nature and are not to be used for navigation. Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The processed swath data are provided as an ASCII x,y,z point data file. These values are not the individual soundings but are the exported BASE (Bathymetry with Associated Statistical Error) surface at 5-meter spatial distances with associated CUBE (Combined Uncertainty and Bathymetry Estimator) sample surface created from the edited soundings dataset. These are considered interpolated samples in which one value represents all soundings within a five-meter node, weighted by uncertainty and proximity, giving the final value as a data sample within the specific grid cell. No manual editing has been applied: no erroneous point removal, interpretation, or validation has been done beyond this point.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2013 (process 1 of 4)
    Swath Bathymetry Acquisition: The IFB data were collected aboard the R/V Sallenger using a Systems Engineering and Assessment Ltd. (SEA) SWATHplus-H 468 kHz interferometric sonar system. Boat position and motion were recorded in real-time using a CodaOctopus F190R wetpod inertial measurement unit (IMU) mounted underwater between the transducer heads to minimize lever arm geometry errors between the observed depths and associated vessel motion. Real-time corrected positions were acquired via the use of the Marinestar HP satellite constellation subscription. Marinestar HP position correction data and motion data from the IMU were integrated with interferometric soundings in the SWATHplus software package versions 3.7.17 with positional and calibration offsets pre-defined by a session file (.sxs), allowing for real-time-corrected depths. A Valeport Mini Sound Velocity Sensor (SVS) was attached to the transducer mount and collected continuous Speed of Sound (SOS) measurements at the depth of the transducers. These values were directly incorporated into the SWATHplus acquisition software giving real-time speed of sound at the transducer while underway. In addition, a separate sound velocity profiler (Valeport miniSVP) was used to collect speed of sound profiles (water surface to seafloor) at intervals throughout the survey.
    Prior to deployment, all equipment offsets between the sonar head and the DGPS antennas were surveyed in dry dock with the use of a laser total station. All the critical physical measurements between the DGPS antennas and the IMU were entered into the Coda F190R program for calibration. The CodaOctopus F190R was calibrated daily and survey operation would commence once calibration status was considered completed and acceptable. All critical physical measurements between the transducers and the IMU were entered into the SWATHplus configuration file (.sxs) for IFB acquisition. Person who carried out this activity:
    Nancy T. DeWitt
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources produced in this process:
    • Several raw data files include SEA SWATHplus configuration files (.sxs) and raw files (.sxr), and sos files (.txt).
    Date: 2013 (process 2 of 4)
    Swath Bathymetry Processing: Position data recorded by the Coda-Octopus F190R IMU system were corrected in real time via the Marinestar HP DGPS. The IMU also applied real-time motion corrections for heave, roll, and pitch to the vertical component of each position fix. The corrected positions were then integrated with the observed bathymetric values to calculate a final ellipsoid height and position representing the elevation of the seafloor with respect to the geodetic reference frame ITRF08 across the swath range. SWATHplus serves as both an acquisition software and initial processing software. Preliminary roll calibration trackline data were collected and processed using SEA SWATHplus and Grid Processor software version 3.7.17 respectively. Instrument offset and calibrations values were input into the session file (.sxs) and the raw data files (.sxr) were then processed using the updated system configuration containing roll calibration values, measured equipment offsets, acquisition parameters, navigation and motion from the F190R, SOS at the sonar head, and SVP cast data. Any calibration offsets or acoustic filtering applied in SWATHplus is also written to the processed data file (.sxp).
    All processed data files were imported into CARIS HIPS and SIPS version 8.1.7, and the original sounding data were edited for outliers using the program's depth filters and reference surfaces. Any remaining outliers were then edited out manually. A CARIS BASE (Bathymetry with Associated Statistical Error) surface with associated CUBE (Combined Uncertainty and Bathymetry Estimator) sample surface was created from the edited soundings dataset. A BASE hypothesis is the estimated value of a grid node representing all the soundings within a chosen resolution or grid-cell size (for example, 5 m) weighted by uncertainty and proximity; giving the final value as a "sample" of the data within the specific grid cell. This algorithm allows for multiple grid-node hypotheses to be verified or overridden by the user, while maximizing processing efficiency. A 5-m resolution CUBE surface was created to perform initial hypothesis editing using the CARIS Subset Editor tool, followed by higher resolution surface detail editing within subset editor. The sample x,y,z data were exported as ASCII text at a 5 x 5-m sample resolution in the ellipsoid datum of ITRF08. Person who carried out this activity:
    Nancy T. DeWitt
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources used in this process:
    • Several raw data files include SEA SWATHplus configuration files (.sxs) and raw files (.sxr), and sos files (.txt).
    Data sources produced in this process:
    • 13BIM02_IFB_LEVEL_05_XXX_ITRF08.txt 13BIM07_IFB_LEVEL_05_XXX_ITRF08.txt 13BIMXXX_IFB_LEVEL_05_XXX_ITRF08.txt
    Date: 2013 (process 3 of 4)
    Datum Transformation: The text file was converted using VDatum version 3.3 from WGS84(G1674) which is equivalent to the International Terrestrial Reference Frame of 2008 (ITRF08) to the North American Datum of 1983 (NAD83) reference frame and the North American Vertical Datum of 1988 (NAVD88) orthometric height using the National Geodetic Survey (NGS) geoid model of 2009 (GEOID09). This file was then converted to Mean Lower or Low Water. Person who carried out this activity:
    Nancy T. DeWitt
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources used in this process:
    • 13BIM02_07_IFB_ITRF08.txt
    Data sources produced in this process:
    • 13BIM02_07_IFB_NAD83_NAVD88_GEOID09.txt
    Date: 13-Oct-2020 (process 4 of 4)
    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?
    The accuracy of the data is determined during data collection. The IFB data were collected during concurrent research cruises in July, and August, 2013. Methods were employed to maintain data collection consistency aboard various platforms. During mobilization, each piece of equipment was isolated to obtain internal and external offset measurements with respect to the survey platform. Each system has a dedicated computer, and efforts were made to utilize the same equipment and software versions on both systems. However, upgrades and changes occur and require additional setup, measurements, and notation. For IFB Differential Global Positioning System (DGPS) information was always implemented for navigational accuracy during acquisition. These bathymetric data have not been independently verified for accuracy.
    For the IFB, offsets between the sonar head and the DGPS antennas were measured and entered into the CodaOctopus F190R internal setup program. DGPS was provided through the Marinestar HP wide-area GPS service. All the critical measurements are recorded manually and digitally and entered into their respective programs for calibration. The CodaOctopus F190R was calibrated daily and survey operation would commence once calibration status was considered completed and acceptable.
  2. How accurate are the geographic locations?
    Navigation information was recorded in real-time kinematic mode via the CODA Octopus F190R Precision Attitude and Positioning System. Differential GPS correction was obtained through the Marinestar High Performance (HP) broadcast subscription from Fugro, Inc. The manufacturer's stated horizontal accuracy is 10 centimeters (cm) 95% of the time. The trackline position data were recorded using HYPACK version 10 hydrographic acquisition and processing software.
  3. How accurate are the heights or depths?
    The manufacturer's stated vertical accuracy of Marinestar HP subscription is 15 cm, 95% of the time. The Coda Octopus F190R IMU, which integrates the Marinestar position with motion, measures vessel velocity (+/- 0.014 meters/second [m/s]), roll and pitch (< 0.025 degrees), heading (1-m baseline 0.1 degrees), and heave (5 cm per meter (m) of depth). The vertical accuracy for the SWATHplus-H system varies with depth and across track range. At 57 m, it is accurate to 10 cm vertically. Maximum vertical transformation error reported by VDatum version 3.2 is 0.171 m or 17.1 centimeters for eastern Louisiana. The sum of the errors (+/-0.15 m + 0.171 m) in the vertical direction is equal to +/-.321 m or +/- 32.1 cm.
  4. Where are the gaps in the data? What is missing?
    These are complete post-processed x,y,z bathymetric data points from acoustic swath data collected in July and August 2013 from the Chandeleur Islands, Louisiana.
  5. How consistent are the relationships among the observations, including topology?
    This file represents the post-processed bathymetric data (x,y,z) collected during a swath bathymetry survey. They represent data coverage for the swath portion of the 2013 Chandleur Island survey, specifically FANs 13BIM02 and 13BIM07. Refer to the online Data Series available at https://doi.org/10.3133/ds1032 for field logs, vessel platform descriptions, and other survey information.

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:
The U.S. Geological Survey requests that it be referenced as the originator of this dataset in any future products or research derived from these data. These data should not be used for navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    Nancy T. DeWitt
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@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?
    This publication was prepared by an agency of the United States Government. Although these data were processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    The ASCII text files contained in the .zip archive can be accessed with any standard text file reader.

Who wrote the metadata?

Dates:
Last modified: 13-Oct-2020
Metadata author:
Nancy T. DeWitt
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
Geologist
600 4th Street South
St. Petersburg, FL
USA

(727) 502-8000 (voice)
ndewitt@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/Chan13_IFB_xyz_metadata.faq.html>
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