10CCT03_ss_1m.tif: the 1-m resolution grid of the side scan sonar data from USGS Cruise 10cct03

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Frequently anticipated questions:

What does this data set describe?

10CCT03_ss_1m.tif: the 1-m resolution grid of the side scan sonar data from USGS Cruise 10cct03
In April of 2010, the U.S. Geological Survey (USGS) conducted a geophysical survey from the east end of West Ship Island, MSiss., extending to the middle of Dauphin Island, Ala. This survey had a dual purpose: (1) to interlink previously conducted nearshore geophysical surveys (shoreline to ~2 kilometers, km) with those of offshore surveys (~2 km to ~9 km) in the ares and (2) to extend the geophysical survey to include a portion of the Dauphin Island nearshore zone. The efforts were part of the USGS 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 geological 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 and to aid scientists in predicting future geomorpholocial 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, particularly in Camille Cut, and provide protection for the historical Fort Massachusetts. For more information refer to <http://ngom.usgs.gov/gomsc/mscip/index.html>.
  1. How might this data set be cited?
    U.S. Geological Survey, DeWitt, Nancy T., Flocks, James G., Pfeiffer, William R., Gibson, James N., and Wiese, Dana S., 20111001, 10CCT03_ss_1m.tif: the 1-m resolution grid of the side scan sonar data from USGS Cruise 10cct03: USGS Data Series Publication DS671, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.883546
    East_Bounding_Coordinate: -88.160394
    North_Bounding_Coordinate: 30.259925
    South_Bounding_Coordinate: 30.116279
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 17-Apr-2010
    Beginning_Time: unknown
    Ending_Date: 28-Apr-2010
    Ending_Time: unknown
    data collection interval
  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 Raster data set. It contains the following raster data types:
      • Dimensions 14996 x 69439 x 1, type Pixel
    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 row and column
      Abscissae (x-coordinates) are specified to the nearest 1
      Ordinates (y-coordinates) are specified to the nearest 1
      Planar coordinates are specified in meters
      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.25722356300003.
      Depth_Datum_Name: Mean lower low water
      Depth_Resolution: 1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    ESRI ArcGIS 9.3 (Source: ESRI ArcMap 9.3.1 GeoTIFF)
    Entity_and_Attribute_Overview: The processed side scan sonar TIFF file is 10cct03_ss_1m.tif
    Entity_and_Attribute_Detail_Citation: http://ngom.usgs.gov/gomsc/mscip/index.html

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
    • Nancy T. DeWitt
    • James G. Flocks
    • William R. Pfeiffer
    • James N. Gibson
    • Dana S. Wiese
  2. Who also contributed to the data set?
    Nancy T. DeWitt, James G. Flocks, William R. Pfeiffer, James N. Gibson, Dana Wiese
  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 multibeam bathymetry and side scan sonar (SSS) data. Data products herein include gridded and interpolated digital depth surfaces, seabed surface backscatter imagery, and x,y,z data products for both multibeam bathymetry and side scan sonar imagery. Additional files include trackline maps, navigation files, Geograpahic Infromation 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 expansion 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: 01-Oct-2011 (process 1 of 3)
    The XTF files collected were converted into CARIS HIPS and SIPS version 7.0 data format structure called Sonar Information Processing System (SIPS) for the purpose of editing and side scan mosaic creation. All horizontal positions were offset relative to a central ship navigation point. The first step in SSS data processing was to correct the altitude, or first return. This was achieved by a combination of auto-prediction parameters set and manual boundary digitization of the water column and seafloor. The second step was application of the beam pattern correction, which was accomplished by sampling a series of beams over homogeneous surface content. The purpose of beam pattern correction is to identify and offset the inherent instrument intensity variance as the across-track range increases. Near nadir the acoustic return is significantly more intense and decreases as across-track range increases. These phenomena result in a false high intensity value strip along the centerline of the SSS swath. Several other SSS editing tools were used, including angle-varying gain and time-varied gain corrections, which were used to further smooth the resulting intensity range artifacts, offering a more consistent along- and across-track image. The despeckle editing tool was also employed to identify and mute isolated pixels having extreme high or low intensity values relative to adjacent pixels. After all the individual side scan lines were examined and edited, Geo-referenced Backscatter Rasters (GeoBars) were created. For this dataset a resolution of 1 m was chosen. From the series of GeoBars, a side scan mosaic image was generated as a composite of the GeoBars, which also provides for a continuous image of a single intensity value range for geographic comparison. Person who carried out this activity:
    William R. Pfeiffer
    Jacobs Technology Inc., Tampa, FL
    Data Analyst
    600 4th Street South
    St. Petersburg, FL

    (727) 803-8747 x3134 (voice)
    Date: 14-Feb-2017 (process 2 of 3)
    Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Alan O. Allwardt
    Contractor -- Information Specialist
    2885 Mission Street
    Santa Cruz, CA

    831-460-7551 (voice)
    831-427-4748 (FAX)
    Date: 13-Oct-2020 (process 3 of 3)
    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)
  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 is complete and calibration status is considered acceptable, then survey operations commence. HYPACK, Inc., HYPSWEEP version 10 was used for the multibeam data acquisition, system calibration,and data post-processing. A patch test was performed at the beginning of the survey to calibrate the SEABAT 8125 and included latency, roll, pitch, and yaw. This involved collecting multibeam data along lines over a sloping surface for the latency, pitch, and yaw tests and over a flat surface for the roll test. The resulting offsets from the patch test were applied to the hardware configuration file prior to survey data acquisition. The Applanix POS MV is not a gyro and therefore did not need calibration. The RESON SeaBat 8125 multibeam transducer head was mounted on a retractable strut-arm that is lowered between the catamaran hulls. Offsets between the sonar head and the DGPS antennas were measured and entered into the respective program. DGPS is always implemented for navigational accuracy. During data acquisition, the differentially corrected positions supplied through the Trimble DSM 212 interface were recorded in the WGS84 datum. Ship heading and motion (roll, pitch, heave) were measured by the Applanix POS MV motion unit. Sound velocity was recorded at the multibeam sonar head. Additional sound velocity casts were conducted at the start and finish of each survey day and as needed throughout the survey. All multibeam bathymetry data were collected using the RESON SeaBat 8125. All side scan sonar data were collected using the Klein 3900 system.
  2. How accurate are the geographic locations?
    Differential navigation was acquired using a local National Geodetic Survey (NGS) Continuously Operating Reference Station (CORS) beacon that broadcasts carrier phase and code range measurements that are captured in real-time using the Applanix Position and Orientation System for Marine Navigation (POS MV). The multibeam bathymetry and side scan sonar data were collected simultaneously using HYSWEEP version 10 and SonarPro version 11.3, respectively. The multibeam bathymetry and the side scan sonar data were collected with separate instruments but utilized the same navigation string from the Applanix POS MV. Unless noted, all DGPS data are referenced to WGS84.
  3. How accurate are the heights or depths?
    The towfish altitude varied considerably during the cruises due to the nature of shallow-water surveying operations. Ideally, SSS is flown at a relatively considerable distance from the vessel and other instruments to avoid acoustical interference. Typical sources of acoustical interference are vessel vibrations and other instruments that utilize similar frequency ranges. However, in shallow-water surveying the optimal distance is difficult to achieve due to the negative buoyancy of the towfish and the effect of unanticipated isolated shoals.
  4. Where are the gaps in the data? What is missing?
    This is a complete processed side scan socar mosaic in GeoTIFF format. 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 or instrument failures.
  5. How consistent are the relationships among the observations, including topology?
    This dataset was completed on 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?
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
  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, 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. Is there some other way to get the data?
  6. What hardware or software do I need in order to use the data set?
    image viewer

Who wrote the metadata?

Last modified: 22-Sep-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:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/ds-671metadata_sidescangrid.faq.html>
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