14BIM02_SBB_xyz: Single-Beam Bathymetry XYZ Data Collected in 2014 Near Breton Island, Louisiana

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Frequently anticipated questions:


What does this data set describe?

Title:
14BIM02_SBB_xyz: Single-Beam 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:
For the single-beam bathymetry, the differential positioning was obtained through post processing the base station data to the rover data. This dataset was transformed from the initial datum ITRF00 to NAD83 using the GEOID09 model (NOAA NGS VDatum software version 3.2 - http://vdatum.noaa.gov/). The final x,y,z position data were gridded at a 10-meter cell size resolution to create the digital elevation model.
  1. How might this data set be cited?
    U.S. Geological Survey, 2016, 14BIM02_SBB_xyz: Single-Beam 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: -89.30402785
    East_Bounding_Coordinate: -89.01420378
    North_Bounding_Coordinate: 29.59867716
    South_Bounding_Coordinate: 29.38737094
  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?
    14BIM02_SBB_03_NAD83_CORS96_UTM16N_NAVD88_GEOID09.txt
    ASCII text file containing the processed single-beam bathymetry x,y,z data 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:276851.9015
    Maximum:304540.4185
    Resolution:0.0001
    NAD83_Y
    NAD83(CORS96) Y-coordinate (northing) of sample point, in meters (Source: VDatum version 3.2)
    Range of values
    Minimum:3253102.2046
    Maximum:3276017.7176
    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:-10.5755
    Maximum:-1.2651
    Resolution:0.0001
    Year
    Year data were collected (Source: USGS) 2014
    DataType
    SBB = Single-Beam Bathymetry; SPCMSC identifier of bathymetry data type. (Source: USGS) Character string - SBB
    DOY
    Day of the year (Source: Attribute_Definition_Source)
    Range of values
    Minimum:195
    Maximum:210
    Resolution:1

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 single-beam bathymetry data collected aboard the R/V Jabba Jaw, in July 2014, around 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.

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 5)
    GPS Acquisition: A GPS base station was erected at a temporarily installed USGS benchmark (BRET) located on the sound side of the Chandeleur Islands. A second base station (BRT2) was temporarily installed on top of a short piling located approximately 0.40 km southwest of the BRET base station location, to provide a backup base station. GPS receivers recorded the 12-channel full-carrier-phase positioning signals (L1/L2) from satellites via the Thales choke-ring antenna at the base stations. A similar GPS instrument combination was duplicated on the survey vessel (rover). The base receivers recorded at 0.1-second intervals and the rover receiver recorded at 1.0-second intervals throughout the survey. 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 5)
    Single-Beam Bathymetry Acquisition: The single-beam bathymetric data were collected aboard the 22-foot R/V Jabba Jaw. Boat motion was recorded at 50-millisecond (ms) intervals using a Teledyne TSS Dynamic Motion Sensor (TSS DMS-05). HYPACK version 14.0.9.47, a marine surveying, positioning, and navigation software package, managed the planned-transect information and provided real-time navigation, steering, correction, data quality, and instrumentation-status information to the boat operator. Depth soundings were recorded at 50-ms intervals using an Odom echotrac CV100 sounder with a 200-kilohertz (kHz) transducer. Data from the GPS receiver, motion sensor, and fathometer were recorded in real-time and merged into a single raw data file (.raw) in HYPACK, with each device string referenced by a device identification code and time stamped to UTC. Sound velocity profile (SVP) measurements were collected using a SonTek Castaway Conductivity, Temperature, and Depth (CTD) instrument. The instrument was periodically cast overboard to observe changes in water column speed of sound (SOS). The recorded profiles were later incorporated during post-processing to correct the depth for temporal and spatial SOS changes throughout the water column. 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:
    • HYPACK raw (*.RAW) data files for each trackline surveyed. HYPACK target files for any targets (*.TGT) recorded digitally while surveying, speed of sound files (*.TXT) in text format.
    Date: 2014 (process 3 of 5)
    Differentially Corrected Navigation Processing: The coordinate values of the GPS base station (BRET and BRT2) are the time-weighted average of values obtained from the National Geodetic Survey On-Line Positioning User Service (OPUS). The base station coordinates were imported into GrafNav version 8.5 (Waypoint Product Group) and the kinematic GPS data from the survey vessel were post-processed to the concurrent GPS session data at the base stations. During processing, steps were taken to ensure that the trajectories between the base and the rover were clean, resulting in fixed positions. By analyzing the graphs, trajectory maps, and processing logs that GrafNav produces for each GPS session, GPS data from satellites flagged by the program as having poor health or satellite time segments that had cycle slips could be excluded, or the satellite elevation mask angle could be adjusted to improve the position solutions. The final differentially corrected, precise DGPS positions were computed at the respective time intervals of the roving GPS (1.0 s) and exported in ASCII text format to replace the uncorrected rover positions recorded during acquisition. The GPS data were processed and exported in the World Geodetic System of 1984 (WGS84 G1150) geodetic datum. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources produced in this process:
    • Post-processed differential navigation data for the rover (boat) in ASCII text format. Three files (forward, reverse, and combined trajectories) are produced for each GPS session file.
    Date: 2014 (process 4 of 5)
    Single-Beam Bathymetry Processing: All data were processed using CARIS HIPS and SIPS (Hydrographic Information Processing System and Sonar Information Processing System) version 8.1.7. The raw HYPACK (version 14.0.9.47) data files were imported into CARIS, the differentially corrected navigation files were imported using the generic data parser tool within CARIS, and any SVP profile casts were entered and edited using the SVP editor within CARIS. The bathymetric data components (position, motion, depth, and SOS) were then merged and geometrically corrected in CARIS to produce processed x,y,z data. Next, the data were edited for outliers and then further reviewed in the Subset Editor utility for crossing status, and questionable data points or areas. The geometrically corrected point data were then exported as an x,y,z ASCII text file referenced to WGS84(G1150), equivalent to ITRF00, and ellipsoid height in meters. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Nancy DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    ndewitt@usgs.gov
    Data sources used in this process:
    • Post-processed differential navigation data, raw HYPACK bathymetric data, and sound velocity data all in ASCII text format.
    Data sources produced in this process:
    • 14BIM02_SBB_Level_03_xxx_ITRF00.txt
    Date: 2015 (process 5 of 5)
    Datum Transformation: The text file 14BIM02_SBB_Level_03_xxx_ITRF00.txt was converted using VDatum version 3.2 from the International Terrestrial Reference Frame of 2000 (ITRF00) 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:
    • 14BIM02_SBB_Level_03_xxx_ITRF00.txt
    Data sources produced in this process:
    • 14BIM02_SBB_03_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 and entered into their respective programs for calibration. Once calibration is complete and calibration status is considered acceptable, survey operations commence. The single-beam systems on each survey platform have a dedicated computer, and efforts are made to utilize the same equipment and software versions for each system and platform. However, upgrades and changes occur and require additional setup, measurements, and notation. For the single-beam bathymetry, offsets between the single-beam transducers and the Ashtech antenna reference point (ARP) were measured and accounted for in post-processing. Bar checks were performed as a calibration check and helped to correct any drift in the echosounder. Differential Global Positioning System (DGPS) coordinates were obtained using post-processing software packages (National Geodetic Survey On-Line Positioning User Service, OPUS, and Waypoint Product Group GrafNav, version 8.5.
  2. How accurate are the geographic locations?
    All static base station sessions were processed through the On-Line Positioning User Service (OPUS) maintained by the National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS). The base location results from OPUS were entered into a spreadsheet to compute a final, time-weighted positional coordinate (latitude, longitude, and ellipsoid height). Base-station positional error for each GPS session was calculated as the absolute value of the final position minus the session position value. The maximum horizontal error of the base station coordinates used for post-processing the single-beam bathymetry was 0.00060 seconds latitude and 0.00125 seconds longitude for the USGS benchmark, BRET, and 0.00023 seconds latitude and 0.00030 seconds longitude for BRT2.
  3. How accurate are the heights or depths?
    All static base station sessions for BRET and BRT2 were processed through On-Line Positioning User Service (OPUS) maintained by the National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS). The base location results from OPUS were entered into a spreadsheet to compute a final, time-weighted positional coordinate (latitude, longitude, and ellipsoid height). Base-station positional error for each GPS session was calculated as the absolute value of the final position minus the session position value. SPCMSC standards define the maximum acceptable vertical error for any individual base station GPS session as less than or equal to three times the standard deviation of the ellipsoid height; any occupations exceeding this error are removed and the base station coordinates are recalculated. For the BRET base station location, the standard deviation of the ellipsoid height was 0.014 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.036 m. For the BRT2 base station location, the standard deviation of the ellipsoid height was 0.012 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.029 m. All the processed single-beam bathymetry data (x,y,z) for 2014 are referenced to these base station coordinates. The differentially corrected navigation files (base station GPS processed to boat GPS) were exported from GrafNav version 8.5 and then imported into CARIS HIPS and SIPS version 8.1.7 and merged, by time, with the HYPACK (versions 13.0.9.17 and 14.0.9.47) raw data files at which point the soundings are then geometrically corrected for motion and speed of sound.
  4. Where are the gaps in the data? What is missing?
    These are complete post-processed x,y,z bathymetric data points from acoustic single-beam bathymetry 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 one single-beam bathymetry (SBB) survey and data coverage for a portion of the 2014 Breton survey, specifically Field Activity Number (FAN) 2015-314-FA, subfan 14BIM02. Refer to the online data series linkage for field logs, vessel platform descriptions, and other survey information; this is directly available at http://pubs.usgs.gov/ds/1005/ds-logs.

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: 19-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)

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