Cat Island Miss. bathymetry collected by the USGS in 2010

Frequently anticipated questions:

What does this data set describe?

Title: Cat Island Miss. bathymetry collected by the USGS in 2010
Abstract:
In September and October of 2010, the U.S. Geological Survey (USGS), in cooperation with the Army Corps of Engineers (USACE), conducted geophysical surveys around Cat Island, Miss. to collect bathymetry, acoustical backscatter, and seismic reflection data (seismic-reflection data have been published separately, Forde and others, 2012). The geophysical data along with sediment vibracore data (yet to be published) will be integrated to analyze and produce a report describing the geomorphology and geologic evolution of Cat Island. Interferometric swath bathymetry, and acoustical backscatter data were collected aboard the RV G.K. Gilbert during the first cruise which took place September 7-15, 2010. Single-beam bathymetry was collected in very shallow water around the island aboard the RV Streeterville from September 28 through October 2, 2010 to bridge the gap between the landward limit of the previous cruise and the shoreline. The survey area extended from the nearshore to approximately 5 kilometers (km) offshore to the north, south, and west, and approximately 2 km to the east. This report archives bathymetry and acoustical backscatter data and provides information and mapping products essential for completion of the project goals. In order to comprehend seafloor surface lithology; acoustic backscatter mosaics, such as the data herein, are used as an aid in determining seafloor material types and extents. The file containing the backscatter data is a 1m GeoTIFF raster data set.
Supplemental_Information:
The U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center assigns a unique identifier to each cruise or field activity. For example, 10BIM04 tells us the data were collected in 2010 (10) for the Barrier Island Monitoring (BIM) study and the data were collected during the fourth (04) 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 field activity ID. Data were collected using the USGS research vessel R/V Gilbert. Side-scan sonar and interferometric swath bathymetry data were collected simultaneously along the tracklines during the geophysical operations. The side-scan sonar tow fish was flown off the port quarter, astern of the vessel. The interferometric swath transducer was pole-mounted off the starboard quarter of the research vessel. Navigation was acquired with a Coda Octopus F190 Precision Attitude and Positioning System and differentially corrected with OmniSTAR HP DGPS constellation. See the digital FACS equipment log for details about the acquisition equipment used. Both raw datasets were stored digitally and processed using SonarPro and CARIS HIPS and SIPS software version 7.1 in the USGS St. Petersburg office. For more information on processing, refer to the Equipment and Processing page. Chirp seismic reflectivity data were also collected during this survey and are archived separately.
  1. How should this data set be cited?

    Buster, Noreen A., Pfeiffer, William R., Miselis, Jennifer L., Kindinger, Jack L., Wiese, Dana S., and U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, 20110131, Cat Island Miss. bathymetry collected by the USGS in 2010: USGS Data Series Publication DS739.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -88.485858
    East_Bounding_Coordinate: -88.171679
    North_Bounding_Coordinate: 30.254499
    South_Bounding_Coordinate: 30.101438

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 07-Sep-2010
    Ending_Date: 15-Sep-2010
    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 30085 x 31919 x 1, type Pixel

    2. What coordinate system is used to represent geographic features?

      The map projection used is Transverse Mercator.

      Projection parameters:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -87.0
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000.0
      False_Northing: 0.0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.5
      Ordinates (y-coordinates) are specified to the nearest 0.5
      Planar coordinates are specified in meter

      The horizontal datum used is D WGS 1984.
      The ellipsoid used is WGS 1984.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    Image pixel values contain acoustic reflectivity values normalized to an 8-bit digital number range (0-255). Lower pixel intensity values correlate with lower signal loss in decibels. The background color is depicted at pixel value 255.
    Entity_and_Attribute_Detail_Citation: GeoTIFF imagery is three bands with pixel values 0 to 255.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    U.S. Geological Survey

  3. To whom should users address questions about the data?

    U.S. Geological Survey
    Attn: Jack Kindinger
    Research Geologist
    600 4th Street South
    St. Petersburg, Florida 33701
    United States

    (727) 803-8747 (voice)
    jkindinger@usgs.gov

Why was the data set created?

These geophysical surveys will provide the data necessary for scientists to define, interpret, and provide acoustic backscatter data for interpretation of sea floor substrate and habitat. Additionally they will aid scientists in proposing theories on future geomorphological changes of the islands with respect to climate change, storm impact, and sea-level rise. Furthermore, these data will provide information for barrier island restoration, anthropogenic effects, and sediment distribution. The dataset herein is a complete side-scan sonar backscatter image for the study area offshore of the above-mentioned area. For more information refer to <http://ngom.usgs.gov/gomsc/mscip/>.

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: 01-Jun-2010 (process 1 of 2)
    Side-scan data acquisition was at sea, collected with a Klein 3900 dual-frequency towfish flown port-quarter of the RV Gilbert. Data were acquired using SonarPro v.11.3 during a cruise in September 2010. Data were collected along planned tracklines approximately 150 meters apart at an average vessel speed of 4 knots. Navigation was calculated by means of DGPS satellite constellation position feed. Navigation data acquisition was at sea, collected with a real-time DGPS system aboard the RV Gilbert. Navigation data were collected in a hydrographic survey software application along planned tracklines approximately 150 meters apart at an average vessel speed of 4 knots.

    Person who carried out this activity:

    Jacobs Technology
    Attn: William R. Pfeiffer
    Data Modeler
    600 4th Street South
    St. Petersburg, Florida 33701

    (727) 803-8747 (voice)
    wpfeiffer@usgs.gov

    Date: 01-Jun-2010 (process 2 of 2)
    Within CARIS SIPS v7.0 data were converted from .xtf format to digitize altitude, filter speckle noise, and apply AVG and TVG corrections. The corrected lines were then used to create Georeferenced Backscatter Rasters (GeoBARs), which were fully blended into a 1 meter/pixel resolution composite mosaic. A complete GeoTIFF was then exported for use in a GIS.

    Person who carried out this activity:

    Jacobs Technology
    Attn: William R. Pfeiffer
    Data Modeler
    600 4th Street South
    St. Petersburg, Florida 33701

    (727) 803-8747 (voice)
    wpfeiffer@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 a single cruise and therefore internally consistent. Methods are employed to maintain data collection consistency aboard various platforms. During mobilization, each piece of equipment (swath and sonar) 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 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. The swath transducer sonar head was pole-mounted on the starboard side of the vessel. Offsets between the sonar head and the Differential Global Positioning System (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.

  2. How accurate are the geographic locations?

    The ship was navigated using the Coda Octopus F190 Precision Attitude and Positioning System. The software used is the F180 Series version 4.0.5. Two antennas received the integrated OmniSTAR High Performance DGPS correction. The software used is F180 Series version 4.0.5. The horizontal accuracy of bathymetric data is at the limit of OmniSTAR, a wide-area differential GPS service, which is within 20 cm. Unless noted, all DGPS data are referenced to WGS84. The swath transducer sonar head was pole-mounted off the starboard quarter of the vessel. Offsets between the sonar head and the DGPS antennas were measured and entered into the F190 internal calibration and setup program.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    There may in some cases be data missing and inconsistent with reported tracklines. This is directly due to the exclusion of poor data, instrument failures, or maybe for the sake of consistent spatial resolution.

  5. How consistent are the relationships among the observations, including topology?

    This dataset was completed on a single and continuous cruise over 4 days from the same research vessel platform.

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 should not be used for navigational purposes. The U.S. Geological Survey requests that it be referenced as the originator of this data set in any future products or research derived from these data.

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Geological Survey
    Attn: U.S. Geological Survey Information Services
    Box 25286, Federal Center
    Denver, CO 80225-0046
    U.S.

    1-888-ASK-USGS (voice)
    infoservices@usgs.gov

  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    This DVD 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, or for general or scientific purposes, 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?

Who wrote the metadata?

Dates:
Last modified: 04-Jun-2012
Metadata author:
Jacobs Technology
Attn: William R. Pfeiffer
Data Modeler
600 Fourth St. South
St. Petersburg, Florida 33701

(727) 803-8747 (voice)
wpfeiffer@usgs.gov

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.18 on Mon Nov 19 11:06:08 2012