14BIM01_IFB_xyz: Interferometric Swath Bathymetry XYZ Data Collected in 2014 Near Breton Island, Louisiana

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Frequently anticipated questions:


What does this data set describe?

Title:
14BIM01_IFB_xyz: Interferometric Swath Bathymetry XYZ Data Collected in 2014 Near Breton Island, Louisiana
Abstract:
As part of the Barrier Island Monitoring Project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted nearshore geophysical surveys off Breton and Gosier Islands, Louisiana, in July and August of 2014. To assist the United States Fish and Wildlife Service (USFWS) with restoration planning efforts, the USGS was tasked with answering fundamental questions about the physical environment of the southern Chandeleur Islands, including the geology, morphology, and oceanography. Baseline data needed to answer these questions was either insufficient or missing in the area. The USGS conducted a comprehensive geologic investigation in the summer of 2014 by collecting geophysical and sedimentological data. Breton Island, located at the southern end of the Chandeleur Island chain, Louisiana, was recognized as a natural and globally important nesting sanctuary for several bird species and was established as the Breton National Wildlife Refuge (NWR) in 1904. The aerial extent of Breton Island has diminished 90% since 1920. Land loss is attributed to ongoing relative sea-level rise, diminished sediment supply, and storm impacts. The bird population on Breton Island has also declined over the years, most notably after Hurricane George in 1998 and Hurricane Katrina in 2015, which completely submerged the island. Despite the decreasing habitable acreage, migratory seabirds continue to return and utilize Breton Island. To prevent the island from being completely submerged in the future and to protect, stabilize, and provide more nesting and foraging areas for the birding population, the USFWS is proposing a restoration effort to rebuild Breton Island to its pre-Katrina footprint. This Data Series serves as an archive of processed interferometric-swath, single-beam bathymetry, and side-scan sonar data collected in the nearshore of Breton and Gosier Islands, NWR, Louisiana. The data were collected during two USGS cruises (USGS Field Activity Numbers 2014-314-FA and 2014-317-FA) in July and August 2014. Geographic Information System data products include a 100 meter-cell-size interpolated bathymetry grid surface, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee (FGDC) metadata.
Supplemental_Information:
The swath bathymetry data were collected and processed in the ITRF2005 geodetic reference frame. This dataset was subsequently transformed using National Oceanic and Atmospheric Administration (NOAA) VDatum version 3.2 transformation software (http://vdatum.noaa.gov/). The data were transformed from ITRF2005 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 and single-beam survey were merged to generate a digital elevation model with a cell-size resolution of 100 meters, which can be downloaded from https://pubs.usgs.gov/ds/1005/ds-data-downloads.html.
  1. How might this data set be cited?
    U.S. Geological Survey, 2016, 14BIM01_IFB_xyz: Interferometric Swath Bathymetry XYZ Data Collected in 2014 Near Breton Island, Louisiana:.

    Online Links:

    This is part of the following larger work.

    DeWitt, Nancy T., Fredericks, Jake J., Flocks, James G., Miselis, Jennifer L., Locker, Stanley D., Kindinger, Jack L., Bernier, Julie C., Kelso, Kyle W., Reynolds, B.J., Wiese, Dana S., and Browning, Trevor, 2015, Archive of bathymetry and backscatter data collected in 2014 nearshore Breton and Gosier Islands, Breton National Wildlife Refuge, Louisiana.: U.S. Geological Survey Data Series 1005, U.S. Geological Survey, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.231252
    East_Bounding_Coordinate: -89.130612
    North_Bounding_Coordinate: 29.484589
    South_Bounding_Coordinate: 29.414692
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 2014
    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?
    14BIM01_IFB_04_5m_NAD83_CORS96_UTM16N_NAVD88_GEOID09.txt
    ASCII text file containing the processed 5-meter resolution interferometric swath bathymetry x,y,z samples transformed to the North American Datum of 1983 (NAD83) geodetic datum and North American Vertical Datum of 1988 (NAVD88) orthometric height, derived using the GEOID09 model. (Source: USGS)
    NAD83_X
    NAD83 (CORS96) X-coordinate (easting) of sample point, in meters (Source: VDatum version 3.2)
    Range of values
    Minimum:283665.7461
    Maximum:293290.744
    Resolution:0.0001
    NAD83_Y
    NAD83(CORS96) Y-coordinate (northing) of sample point, in meters (Source: VDatum version 3.2)
    Range of values
    Minimum:3255999.371
    Maximum:3263569.370
    Resolution:0.0001
    NAVD88_G09
    NAVD88 (orthometric height) of sample point, in meters with respect to GEOID09. (Source: VDatum version 3.2)
    Range of values
    Minimum:-8.2303
    Maximum:-2.3036
    Resolution:0.0001
    StdDev
    The standard deviation of the BASE surface value, in meters (Source: CARIS)
    Range of values
    Minimum:0.000
    Maximum:0.160
    Resolution:0.001
    Year
    Year data were collected (Source: USGS) 2014
    DataType
    IFB = Interferometric Bathymetry; SPCMSC identifier of bathymetry data type. (Source: USGS) Character string - IFB

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?
    Funds for this report are part of project funds for the Louisiana Outer Coast Early Restoration Project, obtained by the natural resource trustees for the Deepwater Horizon Oil Spill, pursuant to the Framework for Early Restoration Addressing Injuries Resulting from the Deepwater Horizon Oil Spill executed April 20, 2011. USFWS is the project lead for the North Breton Island Barrier Island Restoration project. Acknowledgment of the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgment as is standard for citation and legal practices. Sharing of new data layers developed directly from these data would also be appreciated by the U.S. Geological Survey staff. Users should be aware that comparisons with other datasets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photointerpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such.
  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 2014 around Breton Island, located at the southern end of the Chandeleur Island chain, 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: 2014 (process 1 of 3)
    Swath Bathymetry Acquisition: The interferometric swath bathymetry data were collected aboard the R/V Sallenger in July 2014 using the SEA SWATHplus-H 468 kHz interferometric sonar system. The system was fastened to a static pole mount with the sonar transducer in line with the Novatel GPS antennas sitting atop the mount. Boat position and motion data 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 Marinestar HP (High-Precision differential global navigation satellite system) differential subscription service from Fugro, Inc. Marinestar HP position correction data and motion data from the IMU were integrated with interferometric soundings using SWATHplus software, version 3.10.2.0, with positional and calibration offsets pre-defined by a session file (.sxs), allowing for real-time-corrected depths. Before deployment, all equipment offsets were measured. During the survey, all swath tracklines were recorded in SWATHplus raw data format (.sxr). A Valeport Mini Sound Velocity Sensor (miniSVS) was attached to the transducer mount and collected continuous SOS measurements at the depth of the transducers. These values were directly read and incorporated into the SWATHplus raw data format during acquisition providing a real-time speed of sound at the transducer while underway. In addition, a separate Mini Sound Velocity Profiler (Valeport miniSVP) was used to collect speed of sound profiles (water surface to seafloor) approximately every two hours throughout the survey as well as other areas of question such as rapid transitions from shallow to deep. Person who carried out this activity:
    Nancy T. DeWitt
    U.S. Geological Survey's St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Date: 2014 (process 2 of 3)
    Swath Bathymetry Processing: The interferometric swath bathymetry data were collected aboard the R/V Sallenger using a 468 kHz Systems Engineering and Assessment Ltd. (SEA), SWATHplus-H (high frequency) interferometric sonar system. SWATHplus serves as both an acquisition and initial processing software package. Preliminary roll calibration trackline data were collected and processed using SEA SWATHplus version 3.10.2.0 and Grid Processor software version 3.10.0.0. Instrument offsets and calibration values were input into the session file (.sxs), and the raw data files (.sxr) were then processed using the updated system configuration file 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 and acoustic filtering utilized in SWATHplus is then applied to each raw data file to create a processed data file (.sxp), which was then imported into advanced sounding data processing software CARIS HIPS and SIPS® version 8.1. The initial real-time processing datum for the swath and backscatter data was ITRF05, which is the acquisition datum for Marinestar HP position and navigation data. All processed data files (.sxp) were imported into CARIS HIPS and SIPS® version 8.1. Outliers for the navigation data and processed soundings were removed using program filters. Any remaining data outliers were then edited out manually. A CARIS Bathymetry with Associated Statistical Error (BASE) surface with associated Combined Uncertainty and Bathymetry Estimator (CUBE) sample surface was created from the edited soundings. A CUBE 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. 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:
    • 14BIM01_IFB_Level_04_xxx_ITRF05.txt
    Date: 2015 (process 3 of 3)
    Datum Transformation: The text file 14BIM01_IFB_Level_04_xxx_ITRF05.txt was converted using VDatum version 3.2 from the International Terrestrial Reference Frame of 2005 (ITRF05) 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). 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:
    • 14BIM01_IFB_Level_04_xxx_ITRF05.txt
    Data sources produced in this process:
    • 14BIM01_IFB_04_5m_NAD83_CORS96_UTM16N_NAVD88_GEOID09.txt
  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. This dataset is from one research cruise and is therefore internally consistent. Methods are employed to maintain data collection consistency aboard the platform. During mobilization, each piece of equipment is isolated to obtain internal and external offset measurements with respect to the survey platform. All the critical measurements are recorded manually and digitally entered into their respective programs. For the interferometric swath bathymetry, offsets between the sonar head and the DGPS antennas were measured and entered into the CodaOctopus F190R internal setup program. The differential GPS (DGPS) correction is obtained from Marinestar HP, a satellite positioning service, from Fugro, Inc. This signal is received through the Coda Octopus F190R GPS antennas. These bathymetric data have not been independently verified for accuracy.
  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 14.0.9.47 hydrographic acquisition and processing software.
  3. How accurate are the heights or depths?
    The manufacturer's stated vertical accuracy of Marinestar GPS 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 (+/- 0.013 m + +/-0.15 m +0.171 m) in the vertical direction is equal to +/-.334 m or +/- 33.4 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 2014 nearshore Breton and Gosier Islands, southern 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 2014 Breton survey, specifically Field Activity Number (FAN), 2015-315-FA subfan 14BIM01. Refer to the online Data Series available at http://pubs.usgs.gov/ds/1005 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 DVD 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: 20-Mar-2019
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/14BIM01_IFB_xyz_metadata.faq.html>
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