Interpolated digital elevation model (DEM) of the nearshore around Ship, Horn, and Petit Bois Islands, Mississippi: 2016

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Frequently anticipated questions:


What does this data set describe?

Title:
Interpolated digital elevation model (DEM) of the nearshore around Ship, Horn, and Petit Bois Islands, Mississippi: 2016
Abstract:
To characterize coastal change, historical maps and complementary records were compiled including: topographic sheets (T-sheets), hydrographic sheets (H-sheets, smooth sheets), shorelines, and bathymetric soundings surrounding the Mississippi (MS) barrier islands over several time periods (1916-1920, 2008-2009 and 2016). One goal of this work was to create a time-series of bathymetric change maps around the islands. Datasets include 1916 through 1920 soundings collected by the United States Coast and Geodetic Survey as downloaded H-sheets and some digitized soundings from the National Oceanic and Atmospheric Administration (NOAA), 2008 to 2009 soundings collected by the United States Geological Survey St. Petersburg and Woods Hole Coastal and Marine Science Center (USGS SPCMSC and WHCMSC, respectively), and 2016 soundings collected by the USGS SPCMSC in the nearshore environment of Ship, Horn, and Petit Bois Islands. This USGS data release includes three digital elevation models (DEMs) for 1916 to 1920, 2008 to 2009, and 2016; however, this metadata file pertains to the 2016 DEM (2016_MS_NAD83NAVD88g12B_50m.tif). This work was completed in cooperation with the United States Army Corps of Engineers (Mobile, Alabama) and the National Park Service as part of the Mississippi Coastal Improvements Program (MsCIP).
Supplemental_Information:
Elevation XYZ data used to create the 1916 to 1920 and 2008 to 2009 DEMs are included in this USGS data release; 2016 XYZ data can be downloaded from DeWitt and others, 2017. The 1916 to 2009 elevation (z) values were adjusted to account for sea-level rise, using the NOAA tide gauge at Pensacola, FL. For further information on XYZ processing, refer to the accompanying elevation point metadata and Dewitt and others (2017). Within ArcGIS 10.4.1, XYZ soundings for 1916-1920, 2008-2009, and 2016 were used to create Triangular Irregular Network (TIN) surfaces, individual TIN surfaces were later utilized to create a time-series of 50-m bathymetric rasters. All spatial files provided in this data release are referenced to the Universal Transverse Mercator (UTM) North American Datum (NAD83) horizontal datum and North American Vertical Datum of 1988 (NAVD88) GEOID12B.
  1. How might this data set be cited?
    Buster, Noreen A., Brenner, Owen T., and Flocks, James G., 20171121, Interpolated digital elevation model (DEM) of the nearshore around Ship, Horn, and Petit Bois Islands, Mississippi: 2016: 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: -89.003338
    East_Bounding_Coordinate: -88.499847
    North_Bounding_Coordinate: 30.266217
    South_Bounding_Coordinate: 30.187794
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 13-Jul-2016
    Ending_Date: 19-Jul-2016
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 159 x 967, type Grid Cell
    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 row and column
      Abscissae (x-coordinates) are specified to the nearest 50
      Ordinates (y-coordinates) are specified to the nearest 50
      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 (GEOID12B)
      Altitude_Resolution: 0.0001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?

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 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: Jul-2017 (process 1 of 2)
    Using Esri ArcGIS 10.4.1, 2016 SBB and IFB XYZ point data (Dewitt and others, 2017) were used to create a TIN surface using the 'Create TIN' tool within the 3D Analyst toolbox. The subaerial extent (shoreline file) of Ship, Horn, and Petit Bois were assigned the regional operational mean high water (MHW) value of 0.23 m (Weber and others, 2005) by soft clipping the TIN to coincident island shoreline shapefile (2015_shoreline_ShipHorn.shp) modified from Guy, 2015 with the elevation value of 0.23 m (Weber and others, 2005). The TIN was also clipped to the outer spatial extent of reliable data coverage of the XYZ dataset. Person who carried out this activity:
    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
    Date: Jul-2017 (process 2 of 2)
    Using Esri ArcGIS 10.4.1, The TIN dataset for 2016 was used to create gridded raster surfaces using the 'TIN to Raster' tool within the 3D Analyst toolbox. The raster was interpolated using the nearest neighbor algorithm with a 50 m cell size and the processing extent was a common 50-m snap raster (MS2016_snapraster_50m.tif which is included within this data release) used for the interpolation to ensure the pixel cell center locations of the resulting raster matched other DEM rasters in this data release, allowing for direct comparisons. Person who carried out this activity:
    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
  3. What similar or related data should the user be aware of?
    Buster, Noreen A., and Morton, Robert A., 20110404, Historical Bathymetry and Bathymetric Change in the Mississippi-Alabama Coastal Region, 1847-2009: U.S. Geological Survey Scientific Investigations Map SIM 3154, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.

    Online Links:

    DeWitt, Nancy T., Flocks, James G., Pendleton, Elizabeth A., Hansen, Mark E., Reynolds, B.J., Kelso, Kyle W., Wiese, Dana S., and Worley, Charles R., 2012, Archive of single beam and swath bathymetry data collected nearshore of the Gulf Islands National Seashore, Mississippi, from West Ship Island, Mississippi, to Dauphin Island, Alabama: Methods and data report for USGS Cruises 08CCT01 and 08CCT02, July 2008, and 09CCT03 and 09CCT04, June 2009: U.S. Geological Survey Data Series DS 675, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.

    Online Links:

    DeWitt, Nancy T., Stalk, Chelsea A., Fredericks, Jake J., Flocks, James G., Kelso, Kyle W., Farmer, Andrew S., Tuten, Thomas M., and Buster, Noreen A., 2017, Coastal bathymetry data collected in 2016 nearshore from West Ship Island to Horn Island, Gulf Islands National Seashore, Mississippi: U.S. Geological Survey Data Release doi:10.5066/F7B8571Q, St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.

    Online Links:

    Weber, Kathryn M., List, Jeffrey H., and Morgan, Karen L.M., 2005, An Operational Mean High Water Datum for Determination of Shoreline Position from Topographic Lidar Data: U.S. Geological Survey Open-File Report OFR 2005-1027, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    Guy, Kristi K., 2015, Barrier Island Shorelines Extracted from Landsat Imagery: U.S. Geological Survey Open-File Report OFR 2015-1179, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:


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 was determined during data collection. These datasets are from individual research cruises and are therefore internally consistent. Methods were employed to maintain data collection consistency aboard the platform. During mobilization, each piece of equipment was isolated to obtain internal and external offset measurements with respect to the survey platform. All the critical measurements were recorded manually and digitally entered into their respective programs.
    For the interferometric swath bathymetry, (USGS FAN 2016-347-FA, SubFAN 16BIM04), offsets between the sonar head and the DGPS antennas were measured and entered into the CodaOctopus F190R+ internal setup program. The DGPS correction was obtained from Marinestar High-precision (HP) differential global navigation satellite system, a satellite positioning service, from Fugro, Incorporated. This signal was received through the Coda Octopus F190R+ primary GPS antenna. These bathymetric data have not been independently verified for accuracy. The DGPS [default settings] collected coordinate data referenced to the World Geodetic System of 1984 (WGS84) (G1762), which is equivalent at the centimeter level to the International Terrestrial Reference Frame of 2008 (ITRF08).
    For the single beam survey (USGS FAN 2016-347-FA, SubFANs 16BIM05 and 16BIM06), offsets between the single beam transducers, the Ashtech antenna reference point (ARP), and the vessel motion units were measured on the roving vessels. All pertinent measurements were accounted for in the DGPS post processing software packages (National Geodetic Survey On-Line Positioning User Service, OPUS, and Waypoint Product Group GrafNav, version 8.6).
  2. How accurate are the geographic locations?
    For the IFB: The 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 HP broadcast subscription from Fugro, Incorporated. The manufacturer's stated horizontal accuracy is 10 centimeters (cm) 95% of the time. The trackline position data were recorded using HYPACK version 16.1.1.0 hydrographic acquisition and processing software. For the SBB: All static GPS base station sessions were run 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 one final coordinate and error analysis for that base location. Using the OPUS values for each day, and the total time that data were collected each day, the average daily weighted value of occupation time was calculated; longer occupation times held more value than shorter times. The final value for latitude, longitude, and ellipsoid was the weighted average of all the GPS sessions processed with OPUS. This value was entered in GrafNav version 8.6 as the base station coordinates. Error was calculated using daily outputs from OPUS and was calculated as the absolute value of the final value minus the daily value. The maximum horizontal error of the base station coordinates used for post-processing the single beam bathymetry was 0.00026 decimal seconds latitude and 0.00049 decimal seconds longitude for USACE benchmark 202Q, 0.00038 decimal seconds latitude and 0.00033 decimal seconds longitude for SPCMSC benchmark WHRN. The published coordinates were used for the Ship Island benchmark PID BBCL83(4756 F 2011), and the reported error is 0.013 meters latitude and 0.012 longitude.
  3. How accurate are the heights or depths?
    For the IFB: The manufacturer's stated vertical accuracy of Marinestar GPS subscription is 15 cm, 95% of the time. The Coda Octopus F190R+ inertial measurement unit (IMU), which integrates the Marinestar position with motion, measures vessel velocity (+/- 0.014 meters/second [m/s]), roll and pitch (less than 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.
    The IFB data was transformed three times using VDatum version 3.6. The vertical transformation error reported by VDatum are the following: 1) Transformation from ITRF08 to ITRF00 (equivalent to at the centimeter level WGS84_G1150) is 0.000 m or 0.000 cm for the vertical area named CONUS (Conterminous U.S.). The additional, non-VDatum, reference located at the following link lists transformation from ITRF08 to ITRF00 as -0.01050 m or -1.050 cm (https://confluence.qps.nl/download/attachments/29856813/ITRF_Transformation_Parameters.xlsx); 2) Transformation from ITRF00 to NAD83, NAVD88 with respect to GEOID12B is 0.0762 m or 7.62 cm for the vertical area named GEOID12B, and 3) Transformation from NAD83, NAVD88 with respect to GEOID12B to NAD83, MLLW is 0.163 m or 16.30 cm for the vertical area named LAmobile02-8301.
    For the SBB: All static base station sessions for 202Q and WHRN 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 202Q base location, the standard deviation of the ellipsoid height was 0.010 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.023 m. For WHRN base location, the standard deviation of the ellipsoid height was 0.002 m and the maximum difference from the average ellipsoid for any GPS session was +/- 0.022 m. For 4756 F 2011 base location only one OPUS session was run so the published coordinates were used and reported a vertical error of +/- 0.017 m.
    The SBB data was transformed from ITRF00 to NAD83, NAVD88 with respect to GEOID12B using VDatum version 3.6. The vertical transformation error reported by VDatum is 0.0762 m or 7.62cm for the vertical area named GEOID12B.
  4. Where are the gaps in the data? What is missing?
    The data used to create the DEM are complete post-processed XYZ bathymetric data points from acoustic interferometric swath and single beam data collected in July 2016 from the nearshore waters surrounding Ship and Horn Islands, GUIS, Mississippi.
  5. How consistent are the relationships among the observations, including topology?
    This DEM file represents the post-processed bathymetric data collected during USGS FAN 2016-347FA in the nearshore waters surrounding Ship and Horn Islands, Gulf Islands National Seashore, Mississippi (GUIS). Refer to Dewitt and others (2017) 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:
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) 502-8000 (voice)
    nbuster@usgs.gov
  2. What's the catalog number I need to order this data set? 2016_MS_NAD83NAVD88g12B_50m.tif
  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: 15-Apr-2019
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/2016_MS_NAD83NAVD88g12B_50m_metadata.faq.html>
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