10cct01_v2_ss_1m_b.tif

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Frequently anticipated questions:


What does this data set describe?

Title: 10cct01_v2_ss_1m_b.tif
Abstract:
In March of 2010, the U.S. Geological Survey (USGS) conducted geophysical surveys east of Cat Island, Mississippi. 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. The data collected will be used to create baseline bathymetry information that will address seafloor change. This report contains swath bathymetry and side scan sonar data collected aboard the R/V Survey Cat during Cruise 10CCT01. A combination of software packages was used to process and grid the data. This data series describes the methodology used and the resulting data projects.
Supplemental_Information:
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>. The USGS St. Petersburg Coastal and Marine Science Center assigns a unique identifier to each cruise or field activity. For example, 10CCT01 tells us the data were collected in 2010 for the Coastal Change and Transport (CCT) study and the data were collected during the first 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 a 26-foot Glacier Bay Catamaran. Side scan sonar and interferometric swath bathymetry data were collected simultaneously along the tracklines. The side scan sonar towfish was towed off the port side just slightly behind the vessel, close to the seafloor. The interferometric swath transducer was sled-mounted on a rail attached between the catamaran hulls. During the survey the sled is secured into position. Navigation was acquired with a CodaOctopus Octopus F190 Precision Attitude and Positioning System and differentially corrected with OmniSTAR. See the digital FACS equipment log for details about the acquisition equipment used. Both raw datasets were stored digitally and processed using SEA's Ltd. Swath Processor version 3.07 and CARIS HIPS and SIPS software version 7.0 in the St. Petersburg office. For more information on processing, refer to the Equipment and Processing page. Post-processing of the swath dataset revealed a motion artifact that is attributed to movement of the pole that the transducers are attached to in relation to the boat. The survey was forced to take place in the winter months, in which strong winds and rough waves contributed to a reduction in data quality. The rough seas contributed to both the movement of the pole and the very high noise base seen in the raw amplitude data of the side scan sonar. Chirp data were also collected during this survey and are archived separately.
  1. How might this data set be cited?
    U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, DeWitt, Nancy T., Flocks, James G., Pfeiffer, William R., and Wiese, Dana S., 2010, 10cct01_v2_ss_1m_b.tif: USGS Data Series Publication DS563, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, FL.

    Online Links:

    Other_Citation_Details: Data Series 563 File Name = 10cct01_v2_ss_1m_b.tif
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.098401
    East_Bounding_Coordinate: -88.933079
    North_Bounding_Coordinate: 30.286023
    South_Bounding_Coordinate: 30.200723
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 09-Mar-2010
    Beginning_Time: unknown
    Ending_Date: 17-Mar-2010
    Ending_Time: unknown
    Currentness_Reference:
    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 9179 x 15753 x 1, type Pixel
    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 coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 1.000000
      Ordinates (y-coordinates) are specified to the nearest 1.000000
      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.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      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?
    10cct01_v2_ss_1m_b.tif
    ESRI ArcGIS 9.3 (Source: ESRI ArcMap 9.3.1 GeoTIFF)
    X
    WGS84 UTM 16N (Source: World Geodetic System of 1984)
    Range of values
    Minimum:301905
    Maximum:309305
    Y
    WGS84 UTM 16N (Source: World Geodetic System of 1984)
    Range of values
    Minimum:3348375
    Maximum:3351925
    Z
    Coordinate (Source: ESRI ArcGIS 9.3)
    Range of values
    Minimum:-12.60
    Maximum:-2.40
    Units:meters
    Resolution:0.01
    I
    Amplitude Intensity Value (Source: Klein 3900 Side Scan Sonar System measures backscatter as amplitude intensity.)
    Range of values
    Minimum:0
    Maximum:255
    Entity_and_Attribute_Overview:
    The processed side scan sonar TIFF file is 10cct01_v2_ss_1m_b.tif. From this file a text file was created called 10cct01_xyzi.txt the attributes of which are listed below.
    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 - St. Petersburg Coastal and Marine Science Center
    • Nancy T. DeWitt
    • James G. Flocks
    • William R. Pfeiffer
    • Dana S. Wiese
  2. Who also contributed to the data set?
    Nancy T. DeWitt, William R. Pfeiffer, Jim Flocks, 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
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 803-8747 x3058 (voice)
    ndewitt@usgs.gov

Why was the data set created?

This report serves as an archive of the processed swath bathymetry and side scan sonar data. Data products herein include gridded and interpolated surfaces, surface images, and x,y,z data products for both swath bathymetry and side scan sonar imagery. Additional files include trackline maps, navigation files, GIS files, Field Activity Collection System (FACS) logs, and formal FGDC metadata. Scanned images of the handwritten FACS logs are also provided as PDF files. Refer to the Acronyms page for expansion of acronyms and abbreviations used in this report.

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: 2010 (process 1 of 2)
    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 sidescan 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 valueds relative to adjacent pixels. After all the individual sidescan 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 sidescan 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
    USA

    (727) 803-8747 x3134 (voice)
    wpfeiffer@usgs.gov
    Date: 2010 (process 2 of 2)
    Created a text file that combined the swath bathymetry from GeoTIFF file 10cct01_v2rbf_50m.tif with the side scan sonar amplitude intensity from GeoTIFF file 10cct01_v2_ss_b.tif. This was done using ArcMAP version 9.3.1 Spatial Analyst tool. The swath bathymetry and side scan files were combined and then extracted into a table format (DBF) using Spatial Analyst extraction by sample. This table was then exported as a text file named 10cct01_xyzi.txt using XTools Pro version 6.0 export table to text Person who carried out this activity:
    William R. Pfeiffer
    Jacobs Technology Inc., Tampa, FL
    Data Analyst
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 803-8747 x3134 (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 is complete and 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 sled-mounted between the catamaran pontoons. Offsets between the sonar head and the DGPS antennas were measured and entered into the F190 internal setup program. DGPS is always implemented for navigational accuracy. DGPS is normally provided through the OmniSTAR High Performance wide area GPS service unless otherwise noted. All swath bathymetry data was collected using the SEA Ltd., SWATHplus interferometric sonar system. All side scan sonar data was collected using the Klein 3900 system.
  2. How accurate are the geographic locations?
    The ship was navigated using Differential Global Positioning System (DGPS) obtained with the CodaOctopus Octopus F190 Precision Attitude and Positioning System using the F190 Windows software version 4.0.5. Two antennas received the integrated OmniSTAR differential correction. Unless noted, all DGPS data are referenced to WGS84. The swath transducer sonar head was sled-mounted between the catamaran pontoons. Offsets between the sonar head and the DGPS antennas were measured and entered into the F190 internal setup program. The horizontal accuracy of side scan sonar data is at the limit of OmniSTAR, which is within 20 cm.
  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 such as sub-bottom profilers and interferometric swath systems 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. This data provides 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, instrument failures.
  5. How consistent are the relationships among the observations, including topology?
    This dataset was completed on a single and continuous cruise over four 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:
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
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 803-8747 x3012 (voice)
    jflocks@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 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. 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?
    none
  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?

Dates:
Last modified: 27-May-2015
Metadata author:
Nancy T. DeWitt
U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
Geologist
600 4th Street South
St. Petersburg, FL
USA

(727) 803-8747 x3058 (voice)
ndewitt@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/DS_563_ss.faq.html>
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