Tracklines for the Bathymetric Survey USGS Cruise 07CCT01

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Frequently anticipated questions:

What does this data set describe?

Title: Tracklines for the Bathymetric Survey USGS Cruise 07CCT01
The Gulf Islands National Seashore (GUIS) is composed of a series of barrier islands along the Mississippi - Alabama coastline. Historically these islands have been undergoing long-term change. The devastation of Hurricane Katrina in 2005 prompted questions about the stability of the barrier islands and their potential response against future storm impacts. Additionally, there was concern from the National Park Service (NPS) about the preservation of the historical Fort Massachusetts, located on West Ship Island. Prior to 1969, Ship Island was an individual island. In 1969 Hurricane Camille breached Ship Island, widening the cut and splitting it into what is now known as West Ship Island and East Ship Island. In July of 2007, the U.S. Geological Survey (USGS) was able to provide the NPS with a small bathymetry survey of Camille Cut using high-resolution single-beam bathymetry. This provided the GUIS with a post-Katrina assessment of the bathymetry in Camille Cut and along the northern shoreline directly in front of Fort Massachusetts. Ultimately, this survey became an initial bathymetry dataset toward a larger USGS effort included in the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility Project.
For navigational purposes,bathymetric surveys have traditionally been referenced to a water level datum using tide gages and tide models. Bathymetric measurements referenced to a Global Positioning System (GPS) is a more accurate way of representing water depth and has been implemented in the acquisition and processing procedures for these datasets. Previous single-beam bathymetric studies performed at the USGS Center for Coastal and Marine Science have successfully referenced bathymetric measurements to GPS (DeWitt and others, 2007; Hansen 2008 and 2009).
  1. How might this data set be cited?
    DeWitt, Nancy T., Flocks, James G., Reynolds, B.J., and Hansen, Mark, 2012, Tracklines for the Bathymetric Survey USGS Cruise 07CCT01:.

    This is part of the following larger work.

    DeWitt, Nancy T., Flocks, James G., Reynolds, B.J., and Hansen, Mark, 20121023, Archive of Single-Beam Bathymetry Data Collected During USGS Cruise 07CCT01 Nearshore of Fort Massachusetts and within Camille Cut, West and East Ship Islands, Gulf Islands National Seashore, Mississippi, July 2007: U.S. Geological Survey Data Series DS 722, U.S. Geological Survey, Reston, Virginia.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.996405
    East_Bounding_Coordinate: -88.882288
    North_Bounding_Coordinate: 30.248529
    South_Bounding_Coordinate: 30.200405
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 28-Jul-2007
    Ending_Date: 01-Aug-2007
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: remote-sensing image
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (95)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      UTM_Zone_Number: 16
      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 0.000001
      Ordinates (y-coordinates) are specified to the nearest 0.000001
      Planar coordinates are specified in meters
      The horizontal datum used is North American Datum of 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 1/298.25722356300003.
  7. How does the data set describe geographic features?
    ESRI ArcGIS 9.3.1 (Source: ESRI ArcGIS 9.3)
    Internal feature number (Source: ESRI ArcGIS 9.3) Sequential unique whole numbers that are automatically generated
    Feature Geometry (Source: ESRI ArcGIS 9.3) Polyline defining the features.
    Name of trackline from aquisition and post-processing (Source: U.S. Geological Survey)
    Formal codeset
    Codeset Name:###_####
    Codeset Source:First three numbers represent the number of the line and the last four numbers represent the time at which the line was acquired.
    The year the trackline was surveyed (Source: U.S. Geological Survey)
    Range of values
    The survey platform that collected the trackline (Source: U.S. Geological Survey)
    catRV Survey Cat
    This is a shapefile of the ship navigation as recorded using HYPACK version 4.3. The shapefile was created in ArcMap version 9.3.1.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Nancy T. DeWitt
    • James G. Flocks
    • B.J. Reynolds
    • Mark Hansen
  2. Who also contributed to the data set?
    Nancy T. DeWitt, James G. Flocks, B.J. Reynolds, and Mark E. Hansen.
  3. To whom should users address questions about the data?
    Nancy T. DeWitt
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL

    (727) 803-8747 x3058 (voice)

Why was the data set created?

This report serves as an archive of the processed single-beam bathymetry. Data products herein include gridded and interpolated digital depth surfaces and x,y,z data products. Additional files include trackline maps, navigation files, geographic information system (GIS) files, Field Activity Collection System (FACS) logs, and formal Federal Geographic Data Committee (FGDC) metadata. Scanned images of the handwritten FACS logs and digital FACS logs are also provided as PDF files. Refer to the Acronyms page for description of acronyms and abbreviations used in this report or hold the cursor over an acronym for a pop-up explanation.

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: 2007 (process 1 of 2)
    Acquisiton: This is a shapefile of the ship navigation as recorded using HYPACK version 4.3. The shapefile was created in ArcMap version 9.3.1 using the free utility Points 2 Lines version 2. Tracklines were exported from HYPACK version 4.3, converted to a DBG table, and then transformed into a shapefile using Points to Lines version 2.0. Person who carried out this activity:
    Nancy T. DeWitt
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL

    (727) 803-8747 x3058 (voice)
    Date: 2021 (process 2 of 2)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Arnell S. Forde
    600 4th Street South
    St. Petersburg, FL

    (727) 502-8000 (voice)
  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 entered into their respective programs. For 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 calibration efforts and accounted for any drift in the Marimatech Echosounder. Differential Geographic Positioning (DGPS) was obtained using post-processing software packages. 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. The GPS instrument combination at the base station 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 GPS base station data were processed quickly and accurately through one of the three online submittal services commercially available: (1) Automated GPS-Inferred Positioning System (GIPSY), a service provided by National Aeronautic and Space Administration’s (NASA) Jet Propulsion Laboratory, (2) On-Line Positioning User Service (OPUS), maintained by the National Oceanic and Atmospheric Administration (NOAA) and the National Geodetic Survey (NGS), and (3) Scripps Coordinate Update Tool (SCOUT). For the 2007 bathymetry, results from all three services were analyzed independently first. The final x,y,z from each service was then reviewed and averaged together. The SCOUT values differed the most from the average of the three with 1.175 m in the vertical, whereas GIPSY and OPUS differed considerably less at 0.627 m and 0.549 m, respectively. For this reason SCOUT values were not included in the final position, only GIPSY and OPUS and produced +/- 3.9 cm accuracy in the vertical component. This base station position, once finalized, was used as the base x,y,z for post-processing the base GPS to the boat GPS.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This is a complete processed bathymetry shapefile depicting the resultant tracklines for the bathymetric survey. 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?
    This dataset was acquired on one research cruise over the course of 7 days in 2007. Refer to the FACS logs for respective vessel platform and survey information. This dataset was created to show the bathymetry from the cruise. The grid is 50-m spacing.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
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.
Use_Constraints: These data are not to be used for navigation.
  1. Who distributes the data set? (Distributor 1 of 1)
    Jim Flocks
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    600 4th Street South
    St. Petersburg, FL

    (727) 803-8747 x3012 (voice)
  2. What's the catalog number I need to order this data set? Downloadable Data File Name = 07CCT01_50m_hy_tracklines.shp
  3. What legal disclaimers am I supposed to read?
    This CD-ROM publication was prepared by an agency of the United States Government. Although these data have been 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?
    • Availability in digital form:
      Data format: SHP Size: 1.20
      Network links:
      Media you can order: CD-ROM (format CD-R)
    • Cost to order the data: none

  5. Is there some other way to get the data?
  6. What hardware or software do I need in order to use the data set?
    This shapefile was created for use with ESRI ArcGIS software.

Who wrote the metadata?

Last modified: 22-Jun-2021
Metadata author:
Nancy T. DeWitt
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
600 4th Street South
St. Petersburg, FL

(727) 803-8747 x3058 (voice)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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