Coastal bathymetry data collected between 2008 and 2009 offshore of the Mississippi and Alabama barrier islands: Processed elevation point data

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:

What does this data set describe?

Title:
Coastal bathymetry data collected between 2008 and 2009 offshore of the Mississippi and Alabama barrier islands: Processed elevation point data
Abstract:
During the summers of 2008 and 2009 the United States Geological Survey (USGS) conducted bathymetric surveys from West Ship Island, Mississippi, to Dauphin Island, Alabama, as part of the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility project. The survey area extended from the shoreline out to approximately two kilometers and included the adjacent passes. These findings were originally published in Dewitt and others (2012). This USGS data release includes updated elevation point data (xyz) in which NOAA's Vdatum version 3.6 was used convert the 2008-2009 XYZ soundings to Universal Transverse Mercator (UTM) North American Datum of 1983 (NAD83) horizontal datum and North American Vertical Datum of 1988 (NAVD88) GEOID12B vertical datum. One goal of this work was to create time-series of bathymetric change maps around the islands using data collected between 1916 to 1920, 2008 to 2009, and in 2016.
Supplemental_Information:
Single-beam bathymetry (SBB) and interferometric swath bathymetry (IFB) elevation data from surveys in July 2008 and June 2009 were merged into one dataset and published in Dewitt and others (2012) (https://pubs.usgs.gov/ds/675). For this data release, NOAA's Vdatum version 3.6 was used convert the 2008-2009 XYZ soundings to Universal Transverse Mercator (UTM) North American Datum of 1983 (NAD83) horizontal datum and North American Vertical Datum of 1988 (NAVD88) GEOID12B vertical datum. These XYZ point values are used to map coastal bathymetry and create bathymetric changes maps for the area within Esri ArcGIS (version 10.4.1).
  1. How might this data set be cited?
    Buster, Noreen A., Brenner, Owen T., and Flocks, James G., 20171121, Coastal bathymetry data collected between 2008 and 2009 offshore of the Mississippi and Alabama barrier islands: Processed elevation point data: U.S. Geological Survey Data Release doi:10.5066/F7028QFV, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.001529
    East_Bounding_Coordinate: -88.386890
    North_Bounding_Coordinate: 30.271570
    South_Bounding_Coordinate: 30.172387
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 08-Jul-2008
    Ending_Date: 01-Jul-2009
    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?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (1048575)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -87.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: North American Vertical Datum 1988
      Altitude_Resolution: 0.0001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    2008_2009_MS_NAD83NAVD88g12B.txt
    Tab-delimited text file containing the processed 1-meter resolution swath and single-beam bathymetry XYZ samples transformed to the NAD83 geodetic datum and NAVD88 (orthometric height), derived using the GEOID12B model. (Source: USGS)
    X_NAD83
    NAD83 UTM zone 16N X-coordinate (easting) of sample point, in meters (Source: USGS)
    Range of values
    Minimum:307450.000
    Maximum:373273.640
    Resolution:0.001
    Y_NAD83
    NAD83 UTM zone 16N Y-coordinate (northing) of sample point, in meters (Source: USGS)
    Range of values
    Minimum:3339576.760
    Maximum:3349693.666
    Resolution:0.001
    NAVD88g12B
    NAVD88 (orthometric height) of sample point, in meters with respect to GEOID12B. (Source: USGS)
    Range of values
    Minimum:13.313
    Maximum:0
    Resolution:0.0001
    Year
    Year data were collected (Source: USGS)
    Range of values
    Minimum:2008
    Maximum:2009

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Noreen A. Buster
    • Owen T. Brenner
    • James G. Flocks
  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?
    Noreen A. Buster
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL
    USA

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

Why was the data set created?

The purpose of this effort was to use available USGS data to create bathymetric grids and bathymetric change maps around the MS barrier islands to broadly characterize subaqueous morphologic change both spatially and temporally.

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: 2008 (process 1 of 7)
    Process_Description: Acquisition: The single beam data for 2008 were collected using SANDS, which has two components, data acquisition and data processing. The 2008 and 2009 swath bathymetry was collected using the Systems Engineering and Assessment Ltd. (SEA) SWATHplus-H 468 kHz Interferometric System providing both data acquisition and data processing components. The walking kinematic survey of the shoreline was completed using a portable push buggy. Person who carried out this activity:
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    US

    727-502-8000 (voice)
    ndewitt@usgs.gov
    Date: 2008 (process 2 of 7)
    Differentially Corrected Navigation Processing: Each base station GPS file was processed to the respective roving survey platform GPS file using GrafNav version 8.10, a product of Waypoint Product Group. During this process, steps were taken to ensure that the trajectory produced from the base to the rover was clean and produced fixed positions. From these processes a single differentially corrected, precise position at 1-s intervals for each roving GPS session was created Person who carried out this activity:
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    US

    727-502-8000 (voice)
    ndewitt@usgs.gov
    Date: 2008 (process 3 of 7)
    Single Beam Processing: The external navigation files are combined with the raw trackline soundings in SANDS version 3.92. The raw data are geometrically corrected, and GEOID09 was applied. The exported XYZ data are referenced to NAD83 geodetic datum and NAVD88 (orthometric height), derived using the GEOID12B model. Person who carried out this activity:
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    US

    727-502-8000 (voice)
    ndewitt@usgs.gov
    Date: 2008 (process 4 of 7)
    Swath Post-Processing 2008: The raw swath files, (SXR) were run through SWATHplus version 3.06.04.03. The external differential navigation file was substituted for the F190 navigation string; however, the motion (heave, roll, pitch) from the F190 was applied and depths were geometrically corrected. The processed swath files (SXP) were referenced to NAD83, UTM ZONE 16N NAVD88. The SXP files were imported into CARIS HIPS and SIPS version 7.0 with the respective vessel files and merged. Each line was viewed and cleaned in Swath Editor. The filters applied included depth, beam to beam slopes, across-track distance, and missing neighbors. The files were remerged after any changes occurred during the editing process, a 5-m BASE surface was created, and the XYZ data were exported in ASCII format and referenced in NAD83, UTM ZONE 16N NAVD88. Person who carried out this activity:
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    US

    727-502-8000 (voice)
    ndewitt@usgs.gov
    Date: 2009 (process 5 of 7)
    Swath Post-Processing 2009: The SXRs were run through SWATHplus version 3.06.0 without inserting the differential external navigation file. The processed SXP data were imported into CARIS HIPS and SIPS version 6.1. The external navigation files were first smoothed in Matlab version R2007b. The external navigation files were then imported into CARIS with the heave correction (waterline height) offset in the respective vessel file and the navigation data applied as a tide file in CARIS during the merge process. Each line was viewed and cleaned in Swath Editor. The filters applied included depth, beam to beam slopes, across-track distance, and missing neighbors. The files were remerged after any changes occurred during the editing process, a 5-m BASE surface was created, and the XYZ data were exported in ASCII format and referenced to NAD83, UTM ZONE 16N, NAVD88 GEOID09. Person who carried out this activity:
    U.S. Geological Survey – Woods Hole Coastal and Marine Science
    Attn: Elizabeth A. Pendleton
    Geologist
    384 Woods Hole Road
    Woods Hole, MA
    US

    508-457-2259 (voice)
    ependleton@usgs.gov
    Date: 2017 (process 6 of 7)
    Using Vdatum (version 3.6.1) the vertical reference datum of the XYZ point data was converted from NAVD88 GEOID09 to NAVD88 GEOID12B. Vdatum reports vertical uncertainty associated with this transformation as 10.198 centimeters. Person who carried out this activity:
    U.S. Geological Survey – St. Petersburg Coastal and Marine Science
    Attn: Noreen A. Buster
    Geologist
    600 4th Street South
    St. Petersburg, FL
    US

    727-502-8000 (voice)
    nbuster@usgs.gov
    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. These datasets are from four separate research cruises and are therefore internally consistent. Methods are employed to maintain data collection consistency aboard various platforms. During mobilization, each piece of equipment (single beam and swath) 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. Each system has a dedicated computer, and efforts are made to utilize the same equipment and software versions. 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 Ashtch antenna reference point (ARP) were measured and accounted for in post-processing. Bar checks were performed as calibration efforts and accounted for any drift in the Marimatech Echosounder. The Differential Geographic Positioning System (DGPS) information was obtained using post-processing software packages. For the swath bathymetry, offsets between the sonar head and the DGPS antennas were measured and entered into the F190 internal setup program. DGPS is normally provided through the OmniSTAR High Performance wide-area GPS service unless otherwise noted. DGPS is always implemented for navigational accuracy either during acquisition or as a post-processing step.
  2. How accurate are the geographic locations?
    GPS base stations were erected within approximately 15 to 20 km of the survey area. Efforts were made to utilize pre-existing National Geodetic Survey (NGS) benchmarks on the islands. If pre-existing benchmarks were unavailable a USGS benchmark was installed. All static base station sessions were run 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 input into a spreadsheet to conduct error analysis and averaging, and any outliers were removed. For the 2008-2009 base station occupations, results were considered sufficient when +/- 3.3 cm or less accuracy in the vertical component was achieved. These base station positions, once finalized, were used for processing. GPS was recorded using Ashtech Z-Xtreme GPS receivers that record the 12-channel full-carrier-phase positioning signals (L1/L2) from the satellites via the Thales choke-ring antenna. This GPS instrument combination is duplicated on the survey vessel (rover). The base receiver and the rover receiver record their positions concurrently at 1-second (s) recording intervals throughout the survey period. The differential navigation for the single beam bathymetry and the swath bathymetry were both collected in the same manner.
  3. How accurate are the heights or depths?
    Ship motion was measured using the CodaOctopus F190 Precision Attitude and Positioning System. The interferometric sonar is an angle-measuring system; depth accuracy decreases with increasing horizontal range. The swath width of the interferometric sonar varied as a function of depth but generally achieved 5 times the water depth. Vertical accuracy is directly affected by the accuracy of both the navigation system and the sonar system.
  4. Where are the gaps in the data? What is missing?
    This is a complete processed bathymetry and shoreline topography surface in GeoTIFF format. It is a combination of single beam, swath bathymetry, and shoreline topography from USGS cruises 08CCT01, 08CCT02, 09CCT03, and 09CCT04. These data provide a continuous and complete surface; however, there may in some cases be data missing and inconsistent with reported tracklines. This is directly due to the exclusion of poor data and (or) instrument failures.
  5. How consistent are the relationships among the observations, including topology?
    These elevation point datasets were collected on four research cruises over the course of 21 days for 2008 and 20 days for 2009. This dataset was created to show the combination bathymetry and topography from the cruises. It is a combination of single beam and swath bathymetry and shoreline topography from USGS cruises 08CCT01, 08CCT02, 09CCT03, and 09CCT04. These data provide a continuous and complete surface; however, there may in some cases be data missing and inconsistencies due to the exclusion of poor data and (or) instrument failures.

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:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research.
  1. Who distributes the data set? (Distributor 1 of 1)
    Noreen A. Buster
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8114 (voice)
    nbuster@usgs.gov
  2. What's the catalog number I need to order this data set? 2008_2009_MS_NAD83NAVD8812B_XYZ.txt
  3. What legal disclaimers am I supposed to read?
    Although these data have been processed successfully on a computer system at the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The USGS shall not be held liable for improper or incorrect use of the data described or contained herein. Any use of trade, firm, or product 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?

Who wrote the metadata?

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

(727) 502-8000 (voice)
nbuster@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/2008_2009_MS_NAD83NAVD88g12B_XYZ_metadata.faq.html>
Generated by mp version 2.9.50 on Tue Sep 21 18:18:30 2021