13CCT04_IFS_01_ITRF05.tif

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Frequently anticipated questions:


What does this data set describe?

Title: 13CCT04_IFS_01_ITRF05.tif
Abstract:
In August of 2013, the U.S. Geological Survey (USGS) conducted geophysical surveys offshore of Petit Bois Island, Mississippi. These efforts are a continued part of the U.S. Geological Survey Gulf of Mexico Science Coordination partnership with the U.S. Army Corps of Engineers (USACE) to assist the Mississippi Coastal Improvements Program (MsCIP) and the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazards Susceptibility Project, by mapping the shallow geologic stratigraphic framework of the Mississippi Barrier Island Complex. These geophysical surveys will provide the data necessary for scientists to define, interpret, and provide baseline bathymetry and seafloor habitat for this area to aid scientists in predicting future geomorphological changes to the islands with respect to climate change, storm impacts, and sea level rise. Furthermore, these data combined with the geomorphological results will provide the properties and extent of local offshore sand sediment resources available for planning and execution of the Gulf Islands National Seashore barrier island restoration. The geophysical data were collected during one cruise (USGS Field Activity Numbers 13CCT04) aboard the University of Southern Mississippi Research Vessel Tommy Munro offshore along the gulf side of Petit Bois Island, Gulf Islands National Seashore, Mississippi. Data were acquired with the following equipment: a Systems Engineering and Assessment, Ltd., SWATHplus interferometric sonar (468 kilohertz (kHz)), an EdgeTech 424 (4-24 kHz), an EdgeTech 525i chirp sub-bottom profiling system, and a Klein 3900 sidescan sonar system. This report serves as an archive of the processed interferometric swath bathymetry and sidescan sonar data. Geographic information system data products include an interpolated digital elevation model, an acoustic backscatter mosaic, a trackline map, and point data files. Additional files include error analysis maps, Field Activity Collection System logs, and formal Federal Geographic Data Committee metadata. 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.
Supplemental_Information:
The USGS Saint Petersburg Coastal and Marine Science Center (SPCMSC) - St. Petersburg, Fla., assigns a unique identifier to each cruise or field activity. For example, 13CCT04 tells us the data were collected in 2013 during the fourth field activity for that project in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the cruise ID.
  1. How might this data set be cited?
    U.S. Geological Survey, 2014, 13CCT04_IFS_01_ITRF05.tif:.

    Online Links:

    Other_Citation_Details:
    1-Meter Sample Resolution Interferometric Swath Backscatter Data Collected in 2013 offshore of Petit Bois Island, Gulf Islands National Seashore (GUIS) (U.S. Geological Survey Field Activity Number 13CCT04)
    This is part of the following larger work.

    U.S. Geological Survey, DeWitt, Nancy T., Flocks, James G., Kindinger, Jack L., Bernier, Julie C., Kelso, Kyle W., Wiese, Dana S., Finlayson, Dave P., and Pfeiffer, William R., 2014, Archive of Side Scan Sonar and Swath Bathymetry Data Collected During USGS Cruise 13CCT04 Offshore of Petit Bois Island, Gulf Islands National Seashore, Mississippi, August 2014: U.S. Geological Survey Data Series 917, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.542073
    East_Bounding_Coordinate: -88.320286
    North_Bounding_Coordinate: 30.196437
    South_Bounding_Coordinate: 30.072733
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 13-Aug-2013
    Ending_Date: 23-Aug-2013
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: Raster
  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 13060 x 21533, type Grid Cell
    2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.001. Longitudes are given to the nearest 0.001. Latitude and longitude values are specified in decimal degrees. The horizontal datum used is D_ITRF_2005.
      The ellipsoid used is ITRF05 = International Terrestrial Reference Frame 2005.
      The semi-major axis of the ellipsoid used is 6356752.314140356.
      The flattening of the ellipsoid used is 1/298.257222101.
  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)
    • 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?
    U.S. Geological Survey
    Attn: Nancy T. DeWitt
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

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

Why was the data set created?

This 50-meter cell size digital elevation model is an interpretive product that was derived from the processed interferometric swath bathymetry data collected in August of 2014 off of Petit Bois Island, Gulf Islands National Seashore, Mississippi.

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: 2013 (process 1 of 3)
    Swath Bathymetry Acquisition: The interferometric swath bathymetry data were collected aboard the RV Tommy Munro using a SEA SWATHplus-H 468 kHz interferometric sonar system mounted on the starboard side of the vessel. Boat position and motion data were recorded in real-time with 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 with an OmniSTAR HP (High-Precision differential global navigation satellite system) satellite constellation subscription. OmniSTAR HP position correction data and motion data from the IMU were integrated with interferometric soundings in the SWATHplus software package versions 3.7.17, with positional and calibration offsets pre-defined by a session file(.sxs), allowing for real-time- corrected depths. During the survey, all swath tracklines were recorded in SEA SWATHplus raw data format (.sxr). A Valeport Mini Sound Velocity Sensor (SVS) was attached to the transducer mount and collected continuous speed of sound (SOS) measurements at the depth of the transducers. These values were directly read and incorporated into the SWATHplus acquisition software, giving real-time speed of sound at the transducer while underway. In addition, a separate sound velocity profiler (Valeport miniSVP) was used to collect SOS profiles (water surface to seafloor) at intervals throughout the survey. 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
    Date: 2013 (process 2 of 3)
    Swath Bathymetry Processing: Position data recorded by the Coda-Octopus F190R IMU system were corrected in real time via the OmniSTAR HP differential navigation system. The IMU applied real-time motion corrections for heave, roll, and pitch to the vertical component of each position fix. The corrected positions were integrated with the observed bathymetric values to calculate a final ellipsoid height and position, representing the elevation of the seafloor with respect to the geodetic reference frame ITRF05 across the swath range. SWATHplus served as both an acquisition software and initial processing software. Preliminary roll calibration trackline data were collected and processed with Systems Engineering and Assessment Ltd SWATHplus and Grid Processor software version 3.7.17. Instrument offset and calibration values were entered into the session file (.sxs) and the raw data files (.sxr) were processed using the updated system configuration 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 or acoustic filtering applied in SWATHplus was also written to the processed data file (.sxp). The initial real-time processing datum for the swath and backscatter data was ITRF05, which is the acquisition datum for OmniSTAR HP position and navigation data. 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:
    • SWATHplus post processed files (*.sxp).
    Data sources produced in this process:
    • 13CCT04_v2_IFB_04_2m_ITRF05_MLLW.txt
    Date: 2014 (process 3 of 3)
    Interferometric Backscatter Processing: The interferometric backscatter (IFB) was processed using SXPTools (build 175). SXPTools is a research project of the US Geological Survey that uses command line programs to enhance the quality of the backscatter from SEA SWATHplus processed data files using an empirical gain normalization scheme (Finlayson, USGS, unpub. data, 2009). The processed (.sxp) files were gridded using MBSystem (Version 5.3) and exported in ESRI ASCII Grid format. The grid was imported into ESRI's ArcGIS Version 10.2, converted to a raster file with the ASCII to Raster Tool. The final mosaic was exported in GeoTIFF format referenced to ITRF05 UTM Zone 16N. 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:
    • SWATHplus post processed files (*.sxp).
    Data sources produced in this process:
    • 13CCT04_IBS_01_ITRF04.tif
  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. The interferometric swath bathymetry data were collected during concurrent research cruises in August, 2013. Methods are employed to maintain data collection consistency aboard various platforms. During mobilization, each piece of equipment is isolated to obtain internal and external offset measurements with respect to the survey platform. All critical measurements are recorded manually and digitally and entered into their respective programs for calibration. Once calibration is complete and the calibration status is considered acceptable, survey operations commence. Efforts are made to use the same equipment and software versions on the system; however, upgrades and changes can occur and require additional setup, measurements, and notation. 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. DGPS was provided through the OmniSTAR High Performance wide-area GPS service. These bathymetric data have not been independently verified for accuracy.
  2. How accurate are the geographic locations?
    The 2-sigma (95%) horizontal accuracy of the OmniSTAR HP navigation as specified by OmniSTAR, is +/- 10 cm.
  3. How accurate are the heights or depths?
    The 2-sigma (95%) horizontal accuracy of the OmniSTAR HP navigation as specified by OmniSTAR, is +/- 10 cm.
  4. Where are the gaps in the data? What is missing?
    This is a completely processed 1-meter resolution grid of the interferometric swath backscatter data.
  5. How consistent are the relationships among the observations, including topology?
    The interferometric swath bathymetry data were collected during one research cruises in August, 2013. Refer to the online data series linkage for field logs, vessel platform descriptions, and other survey information. This dataset was created to provide a 1-meter grid of the backscatter amplitude data.

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)
    U.S. Geological Survey
    Attn: Nancy DeWitt
    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?
    These shapefiles were created for use with Esri ArcGIS software.

Who wrote the metadata?

Dates:
Last modified: 08-Jun-2016
Metadata author:
U.S. Geological Survey
Attn: Nancy DeWitt
Geologist
600 4th Street South
St. Petersburg, FL
USA

727-502-8000 (voice)
ndewitt@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/13CCT04_IFS_01_ITRF05_metadata.faq.html>
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