2010-003-FA_SSmosaic_BuzzardsBay.tif - Composite sidescan-sonar mosaic collected by the U.S. Geological Survey in Woods Hole, MA offshore of the Elizabeth Islands, MA, 2010 (UTM Zone 19N GeoTIFF)

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Frequently-anticipated questions:

What does this data set describe?

Title:
2010-003-FA_SSmosaic_BuzzardsBay.tif - Composite sidescan-sonar mosaic collected by the U.S. Geological Survey in Woods Hole, MA offshore of the Elizabeth Islands, MA, 2010 (UTM Zone 19N GeoTIFF)
Abstract:
These data were collected under a cooperative agreement between the Massachusetts Office of Coastal Zone Management (CZM) and the U.S. Geological Survey (USGS), Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center (WHCMSC). Initiated in 2003, the primary objective of this program is to develop regional geologic framework information for the management of coastal and marine resources. Accurate data and maps of seafloor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes due to natural or human impacts. The project is focused on the inshore waters of coastal Massachusetts, primarily in water depths of 2-30 meters. Data collected for the mapping cooperative have been released in a series of USGS Open-File Reports (<http://woodshole.er.usgs.gov/project-pages/coastal_mass/html/current_map.html>). The data collected in this study area located around the western extent of the Elizabeth Islands includes high resolution bathymetry, acoustic-backscatter intensity, seismic-reflection, and navigation data. These data were collected during a nearshore cruise in September 2010 onboard the R/V Rafael using the following equipment: an SEA Ltd SwathPlus interferometric sonar (234 kHz), Klein 3000 dual frequency sidescan sonar, an Edgetech 424 chirp subbottom profiling system, and 4 GPS antennae. More information about the cruise conducted as part of the project: Geologic Mapping of the Seafloor Offshore of Massachusetts can be found on the Woods Hole Coastal and Marine Science Center Field Activity webpage: <http://quashnet.er.usgs.gov/data/2010/10003/>
  1. How should this data set be cited?

    U.S. Geological Survey, 2012, 2010-003-FA_SSmosaic_BuzzardsBay.tif - Composite sidescan-sonar mosaic collected by the U.S. Geological Survey in Woods Hole, MA offshore of the Elizabeth Islands, MA, 2010 (UTM Zone 19N GeoTIFF): Open-File Report 2011-1184, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Pendleton, Elizabeth A. , Twichell, David C. , Foster, David S. , Worley, Charles R. , Irwin, Barry J. , and Danforth, William W. , 2012, High-Resolution Geophysical Data From the Sea Floor Surrounding the Western Elizabeth Islands, Massachusetts: Open-File Report 2011-1184, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.994895
    East_Bounding_Coordinate: -70.912163
    North_Bounding_Coordinate: 41.436215
    South_Bounding_Coordinate: 41.387572

  3. What does it look like?

    <https://pubs.usgs.gov/of/2011/1184/GIS_catalog/sidescan/BuzzardsBay_ss.png> (PNG)
    grey scale image of sidescan-sonar mosaic

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

    Calendar_Date: 13-Sep-2010
    Currentness_Reference: 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 Raster data set. It contains the following raster data types:

      • Dimensions 10500 x 13600 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: 19
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -69.000000
      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 0.500000
      Ordinates (y-coordinates) are specified to the nearest 0.500000
      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 1/298.257224.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    There are no attributes associated with a GeoTIFF image. Image pixel values contain acoustic reflectivity values normalized to an 8-bit data range. Low-backscatter is represented by dark tones (low values) and high-backscatter is represented by bright tones (high values). The background color is set to 255 and can be turned off without removing data values.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

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?

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

    David C. Twichell
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2266 (voice)
    508-457-2310 (FAX)
    dtwichell@usgs.gov

Why was the data set created?

This GeoTIFF (Tagged Image File Format) contains sidescan sonar data that were collected in Sept. 2010. These data are used to define the sea-floor morphology on the Buzzards Bay side of the western Elizabeth Islands of Massachusetts

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Type_of_Source_Media: disc
    Source_Contribution:
    Sidescan-sonar (acoustic-backscatter) data were acquired with a Klein 3000 dual-frequency sidescan-sonar system (100 and 500 kHz), which was towed approximately 3 m astern from a port-side davit. Klein SonarPro acquisition software was used to log the data digitally at a sample rate resulting in raw pixel resolutions of approximately 0.18 and 0.14 m in the across-track and along-track directions, respectively. Horizontal offset values between the sidescan fish and DGPS antenna were provided to SonarPro, which calculated fish position dynamically during acquisition. The Klein system produced useable data over swath widths of 150-m during cruise 2010-003-FA.

  2. How were the data generated, processed, and modified?

    Date: 2010 (process 1 of 3)
    Within XSonar Software (version: 2.0) a median filtering routine (Malinverno and others, 1990) was applied to the raw 100 kHz sidescan-sonar data (.xtf) to remove speckle noise during demultiplexing; the filter was 4 pixels across track by 3 pixels along track. Also the usual normalize values (value = 4095) were modified for the starboard-side, because the transducer was malfunctioning and causing darker backscatter tones. A value of 1024 was used on the starboard channel, while 4095 was the noramilize value for the port. Some additional stripeyness exists in the mosaic due to acquisition gain adjustments and troubleshooting on the starboard transducer. The data were further processed to correct for fish altitude, slant and beam artifacts, and then merged with the navigation (Danforth, 1997). Odd and even sidescan sonar lines were mapped separately out of XSonar at 0.5 meter/pixel resolution. Sidescan areas were defined within the cruise domain such that the sonar images mapped in XSonar would be no larger than 200 Mb.

    Person who carried out this activity:

    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2259 (voice)
    (508) 457-2310 (FAX)
    ependleton@usgs.gov

    Date: 2010 (process 2 of 3)
    The odd and even area files were imported into PCI Geomatica Software (version 10.1) to be digitally mosaicked together using PCI's OrthoEngine and procedures described in Paskevich (1996). The mosaicking process produces an enhanced, geographically correct, sidescan-sonar mosaic with 0.5 meter/pixel resolution. The composite mosaic was exported as a GeoTIFF image.

    Person who carried out this activity:

    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2259 (voice)
    (508) 457-2310 (FAX)
    ependleton@usgs.gov

    Date: 2011 (process 3 of 3)
    The mosaicked 8-bit tiff was brought into Photoshop (CS4 -- 64 bit) and the histogram was stretched to show the contrast in the seafloor image. In photoshop select: Adjust -- Levels.

  3. What similar or related data should the user be aware of?

    Danforth, W.W., O'Brien, T.F., and Schwab, W.C., 1991, USGS image processing system: near real-time mosaicking of high-resolution sidescan-sonar data: Vol. 32, No. 1, Sea Technology, Arlington, VA.

    Danforth, William W. , 1997, XSonar/ShowImage: A complete system for rapid sidescan-sonar processing and display.: Open-File Report 97-686, U.S. Geological Survey, Woods Hole, MA.

    Malinverno, A., Edwards, M., and Ryan, W.B.F., 1990, Processing of SeaMARC swath sonar data.: 15, Journal of Oceanic Engineering, Picayune, MS.

    Paskevich, V.F., 1996, MAPIT: An improved method for mapping digital sidescan sonar data using the Woods Hole Image Processing System (WHIPS) Software: Open-File Report 96-281, U.S. Geological Survey, Woods Hole, MA.

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

    The navigation for these data were acquired with a Communications Systems International (CSI), Inc. LGBX Pro Differential Global Positioning System (DGPS) receiver and an antenna mounted on the cabin of the R/V Rafael. All DGPS data are referenced to WGS84. The horizontal distance (both x and y) between towed sidescan sonar fish and the mounted GPS antennae were measured on the ship and the correction was applied in the Klein SonarPro acquisition software. The differential GPS is accurate within 1 to 2 meters. The layback of the towfish adds additional uncertainty due to changes in angle and scope of the tow cable in response to sea state and vessel speed. The total horizontal uncertainty is + or - 10 meters.

  3. How accurate are the heights or depths?

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

    All available data within the mosaic area were used to create the backscatter mosaic.

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

    All sidescan data were collected during USGS-WHCMSC cruise 2010-003-FA using a Klein 3000 dual frequency sidescan-sonar towfish and a CSI LGBX Pro DGPS. Quality control was conducted during processing of the data. Any spurious data or artifacts were removed or minimized.

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:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.

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

    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2259 (voice)
    (508) 457-2310 (FAX)
    ependleton@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?

    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    This zip file contains a GeoTIFF image. To utilize these data, the user must have an image viewer, image processing or GIS software package capable of importing a GeoTIFF image.

Who wrote the metadata?

Dates:
Last modified: 18-Nov-2011
Metadata author:
Elizabeth A. Pendleton
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700x2259 (voice)
(508) 457-2310 (FAX)
ependleton@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.8.25 on Fri Nov 18 14:46:57 2011