Single-Beam Bathymetry XYZ Data Collected in 2015 from Grand Bay, Alabama/Mississippi

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Frequently anticipated questions:

What does this data set describe?

Title:
Single-Beam Bathymetry XYZ Data Collected in 2015 from Grand Bay, Alabama/Mississippi
Abstract:
As part of the Sea level and Storm Impacts on Estuarine Environments and Shorelines project (SSIEES), scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted a single-beam bathymetry survey within the estuarine, open bay and tidal creek environments of Grand Bay Alabama/Mississippi, from May to June 2015. The goal of the SSIEES project is to assess the physical controls of sediment and material exchange between wetlands and estuarine environments along the northern Gulf of Mexico, specifically Grand Bay AL/MS and Vermilion Bay, Louisiana, as well as along the east coast in Chincoteague Bay Virginia/Maryland. The data included in this data release provide baseline bathymetric information for future research investigating wetland/marsh evolution, sediment transport, recent and long term geomorphic change, and can also support modeling of future changes in response to restoration and storm impacts. The survey area encompasses more than 40 square kilometers (km2) of Grand Bay’s incorporated waters. This data release serves as an archive of processed single-beam bathymetry data, collected from May 28 to June 3, 2015 (USGS Field Activity Number [FAN] 2015-315-FA). Geographic information system (GIS) data products include: a 10- and 30-meter cell size interpolated bathymetry grid, trackline maps, and point data files. Additional files include error analysis maps, Field Activity Collection System (FACS) 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, which used the International Terrestrial Reference Frame of 2000 (ITRF00) to the North American Datum of 1983 (NAD83) geodetic datum and North American Vertical Datum of 1988 (NAVD88) orthometric height, using the GEOID12A model as well as NAD83 mean lower low water (MLLW) (NOAA NGS VDatum software version 3.6 - http://vdatum.noaa.gov/). The final x,y,z sounding data were gridded at a 10- and 30-meter cell size resolution to create the digital elevation models, which are also included in this data release.
  1. How might this data set be cited?
    U.S. Geological Survey, 20180405, Single-Beam Bathymetry XYZ Data Collected in 2015 from Grand Bay, Alabama/Mississippi: U.S. Geological Survey Data Release doi:10.5066/F7NP22M2, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

    This is part of the following larger work.

    DeWitt, Nancy T., Stalk, Chelsea A., Smith, Christopher G., Locker, Stanley D., Fredericks, Jake J., McCloskey, Terrance A., and Wheaton, Cathryn J., 20171201, Single-Beam Bathymetry Data Collected in 2015 from Grand Bay, Alabama/Mississippi: U.S. Geological Survey Data Series 1070, U.S. Geological Survey, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.41297442
    East_Bounding_Coordinate: -88.31118702
    North_Bounding_Coordinate: 30.40988996
    South_Bounding_Coordinate: 30.34067113
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 28-May-2015
    Ending_Date: 03-Jun-2015
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Tabular 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?
    Grand_Bay_2015_SBB_ITRF00.txt
    ASCII text file containing the processed single beam bathymetry x,y,z data in the native format of WGS84 (ITRF00) ellipsoid height. (Source: OPUS)
    ITRF00_X
    WGS84 (ITRF00) X-coordinate (easting) of sample point, in meters. (Source: OPUS)
    Range of values
    Minimum:364277.197
    Maximum:373969.113
    Resolution:0.001
    ITRF00_Y
    WGS84 (ITRF00) Y-coordinate (northing) of sample point, in meters. (Source: OPUS)
    Range of values
    Minimum:3357380.344
    Maximum:3364936.442
    Resolution:0.001
    ITRF00_Lat
    WGS84 (ITRF00) latitude of sample point, in meters. (Source: OPUS)
    Range of values
    Minimum:30.340961
    Maximum:30.409386
    Resolution:0.000001
    ITRF00_Lon
    WGS84 (ITRF00) longitude of sample point, in meters. (Source: OPUS)
    Range of values
    Minimum:-88.412586
    Maximum:-88.311718
    Resolution:0.000001
    Year
    Year of acquisition. (Source: USGS) 2015 - Year of acquisition.
    DOY
    Day of Year (Julian Day) of acquisition. (Source: USGS)
    Range of values
    Minimum:148
    Maximum:154
    HypackLine
    Line identifier assigned at time of acquisition. (Source: USGS) Uses planed line number coupled with vessel FAN and start time for the line.
    GPS_Week
    GPS week of acquisition. (Source: OPUS)
    Range of values
    Minimum:1846
    Maximum:1847
    GPS_Second
    GPS second of acquisition. (Source: OPUS)
    Range of values
    Minimum:53477.131
    Maximum:593283.851
    Resolution:0.001
    Ellipsoid
    Ellipsoid height of sample point, in meters. (Source: OPUS)
    Range of values
    Minimum:-33.36
    Maximum:-29.53
    Resolution:0.01
    DataType
    SBB- Single-beam Bathymetry (Source: USGS) Type of acquisition - Single-beam Bathymetry
    FAN
    Field Activity Number (Source: USGS) Sub-cruise identifier/field activity number assigned per vessel (15CC04 = RV Shark, 15CCT05 = RV Chum)
    NAD83_X
    NAD83 (CORS96) X-coordinate (easting) of sample point, in meters. (Source: VDatum version 3.6)
    Range of values
    Minimum:364277.9500
    Maximum:373969.8838
    Resolution:0.0001
    NAD83_Y
    NAD83 (CORS96) Y-coordinate (northing) of sample point, in meters. (Source: VDatum version 3.6)
    Range of values
    Minimum:3357379.7465
    Maximum:3364935.8426
    Resolution:0.0001
    Year
    Year of acquisition. (Source: USGS) 2015 - Year of acquisition.
    DOY
    Day of Year (Julian Day) of acquisition. (Source: USGS)
    Range of values
    Minimum:148
    Maximum:154
    HypackLine
    Line identifier assigned at time of acquisition. (Source: USGS) Uses planed line number coupled with vessel FAN and start time for the line.
    GPS_Week
    GPS week of acquisistion. (Source: OPUS)
    Range of values
    Minimum:1846
    Maximum:1847
    GPS_Second
    GPS second of acquisition. (Source: OPUS)
    Range of values
    Minimum:53477.131
    Maximum:593283.851
    Resolution:0.001
    NAVD88_G12
    NAVD88 (orthometric height) of sample point, in meters, with respect to GEOID12A. (Source: VDatum version 3.2)
    Range of values
    Minimum:-3.9457
    Maximum:-0.0054
    Resolution:0.0001
    DataType
    SBB- Single-beam Bathymetry (Source: USGS) Type of acquisition - Single-beam Bathymetry
    FAN
    Field Activity Number (Source: USGS) Sub-cruise identifier/field activity number assigned per vessel (15CC04 = RV Shark, 15CCT05 = RV Chum)
    Grand_Bay_2015_SBB_NAD83_MLLW.txt
    ASCII text file containing the processed single-beam bathymetry x,y,z data transformed to the North American Datum of 1983 (NAD83) Mean Lower Low Water (MLLW). (Source: USGS)
    NAD83_X
    NAD83 (CORS96) X-coordinate (easting) of sample point, in meters. (Source: VDatum version 3.6)
    Range of values
    Minimum:364277.95
    Maximum:373969.88
    Resolution:0.01
    NAD83_Y
    NAD83 (CORS96) X-coordinate (easting) of sample point, in meters. (Source: VDatum version 3.6)
    Range of values
    Minimum:3357379.74
    Maximum:3364895.15
    Resolution:0.01
    Year
    Year of acquisition. (Source: USGS) 2015 - Year of acquisition.
    DOY
    Day of Year (Julian Day) of acquisition. (Source: USGS)
    Range of values
    Minimum:148
    Maximum:154
    HypackLine
    Line identifier assigned at time of acquisition. (Source: USGS) Uses planed line number coupled with vessel FAN and start time for the line.
    GPS_Week
    GPS week of acquisition. (Source: OPUS)
    Range of values
    Minimum:1846
    Maximum:1847
    GPS_Second
    GPS second of acquisition. (Source: OPUS)
    Range of values
    Minimum:53477.131
    Maximum:593283.851
    Resolution:0.001
    MLLW
    Mean Lower Low Water (MLLW) height of sample point, in meters. (Source: VDatum version 3.6)
    Range of values
    Minimum:-3.8345
    Maximum:0.1081
    Resolution:0.0001
    DataType
    SBB- Single-beam Bathymetry (Source: USGS) Type of acquisition - Single-beam Bathymetry.
    FAN
    Field Activity Number (Source: USGS) Sub-cruise identifier/field activity number assigned per vessel (15CC04 = RV Shark, 15CCT05 = RV Chum)

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 (SPCMSC).
  3. To whom should users address questions about the data?
    Chelsea A. Stalk
    Cherokee Nation Technologies/U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    Researcher I
    600 4th Street South
    St. Petersburg, FL
    USA

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

Why was the data set created?

This zip archive, 2015-315-FA_SBB_xyz.zip, contains processed x,y,z data points for all single-beam bathymetry data collected under FAN 2015-315-FA, which encompasses data from two separate survey platforms: the RV Shark (15CCT04), and RV Chum (15CCT05), during the May-June 2015 Grand Bay, Mississippi/Alabama survey. Additional survey details are available at https://cmgds.marine.usgs.gov/fan_info.php?fan=2015-315-FA.

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: 2015 (process 1 of 7)
    GPS Acquisition: The Geographic Positioning Systems (GPS) base stations were occupied by USGS personnel for the purpose of this survey. Bench mark B166 was located to the north-north west of the survey area near the railroad tracks at the entrance of the Grand Bay National Estuarine Research Reserve (GBNERR), 189A was located northwest of the survey area at the boat launch location used for this survey. The base stations were equipped with Ashtech Proflex GPS Receivers recording 12-channel full-carrier-phase positioning signals (L1/L2) from satellites via Thales choke-ring antennas, recording at 0.1 seconds (s), using WGS84 (G1150), equivalent to ITRF00, and ellipsoid height, in meters. 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: 2015 (process 2 of 7)
    Single-beam Bathymetry Acquisition: The single-beam bathymetric data were collected under USGS FAN 2015-315-FA, which encompasses two sub-cruise identifiers specific to platform (15CCT04, 15CCT05). The RV Shark (15CCT04), a 12-foot (ft) Yamaha Personal Water Craft (PWC) collected 298.8 line-km (158 lines), and the RV Chum (15CCT05), an additional 12-ft Yamaha PWC collected 312.6 line-km (123 lines). A motion sensor device was not used for either vessel. Rather, to minimize motion errors, both RV Shark and RV Chum recorded GPS data at 0.1-seconds, utilized a short antenna height by use of a lever arm, and was outfitted with narrow (4-degree) transducer beam. HYPACK (version 13.0.09.17), 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 vessel 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, and fathometer were recorded in real-time aboard both vessels independently 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 Coordinated Universal Time (UTC). Sound velocity profile (SVP) measurements were collected using two SonTek Castaway conductivity, temperature, and depth (CTD) instruments. The instruments were periodically cast overboard to observe changes in water column speed of sound (SOS). A total of 74 sound velocity casts were taken throughout the survey in water depths ranging from 0.135 to 3.95 m. The average sound velocity recorded was 1521.4 meters per second (m/s), and values ranged from 1515.6 to 1527.0 m/s. 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: 2015 (process 3 of 7)
    Differentially Corrected Navigation Processing: The coordinate values of the GPS base stations (B166, 189A) are the time-weighted average of values obtained from OPUS. The base station coordinates were imported into GrafNav version 8.7 (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 (0.1-s for 15CCT04, 15CCT05) 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 (PWC) were exported in ASCII text format. Three files (forward, reverse, and combined trajectories) are produced for each GPS session file.
    Date: 2015 (process 4 of 7)
    Single-beam Bathymetry Processing: All data were processed using CARIS HIPS and SIPS (Hydrographic Information Processing System and Sonar Information Processing System) version 9.0.17. The raw HYPACK (version 13.0.09.17) 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. The bathymetric data components (position, 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 T. 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:
    • Grand_Bay_2015_SBB_Level_02_ITRF00.txt
    Date: 2015 (process 5 of 7)
    Quality Control and Quality Assurance (QA/QC): All single-beam data found in the ASCII file exported from CARIS were imported into Esri ArcMap version 10.3.1, where a shapefile of the individual data points (x,y,z) was created and plotted in 1-m color coded intervals. First, all data were visually scanned for any obvious outliers or problems. A Python script was used for the purpose of evaluating elevation differences at the intersection of crossing tracklines by calculating the elevation difference between points at each intersection using an inverse distance weighting equation. GPS cycle slips, stormy weather conditions, and rough sea surface states can contribute to poor data quality. If discrepancies that exceed the acceptable error threshold were found, then the line in error was either removed or statically adjusted. The script was run on all vessel point data first on a vessel by vessel basis and then run a final time for all data points from all vessels collectively. Once the dataset passed all QA/QC procedures and manual editing steps, the data were considered final and included in the download files of this data release. 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 used in this process:
    • Grand_Bay_2015_SBB_Level_02_ITRF00.txt
    Data sources produced in this process:
    • Grand_Bay_2015_SBB_Level_03_ITRF00.txt, Grand_Bay_2015_SBB_ITRF00.txt
    Date: 2015 (process 6 of 7)
    Datum Transformation: The text file of the final XYZ soundings, was converted using version 3.6 of NOAA’s VDatum software conversion tool (reported vertical transformation error is 5.4 cm) from ITRF00 to the NAD83 reference frame and NAVD88 orthometric height using the NGS geoid model of 2012 (GEOID12A) and MLLW. 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 used in this process:
    • Grand_Bay_2015_SBB_ITRF00.txt
    Data sources produced in this process:
    • Grand_Bay_2015_SBB_NAD83_NAVD88_GEOID12A.txt, Grand_Bay_2015_SBB_NAD83_MLLW.txt
    Date: 13-Oct-2020 (process 7 of 7)
    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. This dataset is from one research cruise and is therefore internally consistent. Methods are employed to maintain data collection consistency aboard both platforms (15CCT04, 15CCT05). 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, then 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 [NGS] On-Line Positioning User Service [OPUS] and Waypoint Product Group GrafNav, version 8.7).
  2. How accurate are the geographic locations?
    All static base station sessions were processed through OPUS, which is maintained by the National Oceanic and Atmospheric Administration (NOAA) and the NGS. The base location results from OPUS were entered into a spreadsheet to compute a final, time-weighted positional coordinates (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 0.00025 seconds latitude and 0.00044 seconds longitude for the USGS benchmark, 189A, 0.00040 seconds latitude and 0.00164 seconds longitude for B166.
  3. How accurate are the heights or depths?
    Both static base station sessions (B166, 189A) were processed through OPUS maintained by NOAA and the NGS. The base location results from OPUS were entered into a spreadsheet to compute a final, time-weighted positional coordinates (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 B166 base station location, the standard deviation of the ellipsoid height was 0.017 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.038 m. For the 189A 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 +/- 0.017 m. All the processed single-beam bathymetry data (x,y,z) for 2015 are referenced to these base station coordinates. The differentially corrected navigation files (base station GPS processed to rover GPS) were exported from GrafNav version 8.7 and then imported into CARIS HIPS and SIPS version 9.0.17 and merged, by time, with the HYPACK (version 13.0.09.17) 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?
    This dataset is considered complete for the information presented, as described in the abstract section. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    These datasets are from one field activity with consistent instrument calibrations.

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:
These data are scientific in nature and are not to be used for navigation. 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)
    Chelsea A. Stalk
    Cherokee Nation Technologies/U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Researcher I
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8000 (voice)
    cstalk@usgs.gov
  2. What's the catalog number I need to order this data set? Grand_Bay_2015_SBB_ITRF00.txt, Grand_Bay_2015_SBB_NAD83_MLLW.txt, Grand_Bay_2015_SBB_NAD83_NAVD88_GEOID12A.txt
  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:
Chelsea A. Stalk
Cherokee Nation Technologies/U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
Researcher I
600 4th Street South
St. Petersburg, FL
USA

(727) 502-8000 (voice)
cstalk@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/2015-315-FA_SBB_xyz_metadata.faq.html>
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