H11045_1M.tif: Composite Mosaic of Sidescan Sonar NOAA Survey H11045

Metadata also available as OUTLINE | TEXT

Frequently-anticipated questions:

What does this data set describe?

H11045_1M.tif: Composite Mosaic of Sidescan Sonar NOAA Survey H11045
The U.S. Geological Survey, in cooperation with the National Oceanic and Atmospheric Administration and the Connecticut Department of Environmental Protection, has produced detailed geologic maps of the sea floor in Long Island Sound, a major East Coast estuary surrounded by the most densely populated region of the United States. These studies have built upon cooperative research with the State of Connecticut that was initiated in 1982. The current phase of this research program is directed toward studies of sea-floor sediment distribution, processes that control sediment distribution, nearshore environmental concerns, and the relation of benthic community structures to the sea-floor geology.

Anthropogenic wastes, toxic chemicals, and changes in land-use patterns resulting from residential, commercial, and recreational development have stressed the environment of the Sound, causing degradation and potential loss of benthic habitats (Koppelman and others, 1976; Long Island Sound Study, 1994). Detailed maps of the sea floor are needed to help evaluate the extent of adverse impacts and to help manage resources wisely in the future. Therefore, in a continuing effort to better understand Long Island Sound, we have constructed and interpreted sidescan sonar mosaics (complete-coverage acoustic images of the sea floor) within specific areas of special interest. The mosaic presented herein covers a 190.3 km square area of the sea floor in the West-Central Basin of Long Island Sound.

The mosaics and their interpretations serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The sidescan sonar mosaics also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretation of point measurements.

  1. How should this data set be cited?

    National Oceanic and Atmospheric Association, 2005, H11045_1M.tif: Composite Mosaic of Sidescan Sonar NOAA Survey H11045:, U.S. Geological Survey, Coastal and Marine Geology, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details: Data are released via DVD
    This is part of the following larger work.

    Beaulieu, E., Poppe, L.J., Paskevich, V.F., Doran, E.F., Chauveau, B.E., Crocker, J.M., Beaver, A.L., and Schattgen, P.T., 2005, Sidescan Sonar Imagery and Surficial Geologic Interpretation of the Sea Floor off Bridgeport, Connecticut: Open-File Report 2005-1162, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -73.306786
    East_Bounding_Coordinate: -73.106895
    North_Bounding_Coordinate: 41.153685
    South_Bounding_Coordinate: 41.018163

  3. What does it look like?

    <http://pubs.usgs.gov/of/2005/1162/graphics/h11045_1m.jpg> (JPEG)
    Overview of the digital sidescan sonar mosaic in UTM produced for NOAA survey H11045

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

    Calendar_Date: 2004
    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 20886 x 17164 x 1, type Pixel

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      UTM_Zone_Number: 18
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -75.000000
      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 0.000010
      Ordinates (y-coordinates) are specified to the nearest 0.000010
      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?


    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.





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?

    U.S. Geological Survey
    c/o Larry Poppe
    384 Woods Hole Rd.
    Woods Hole, MA 02543

    (508) 548-8700 x2314 (voice)
    (508) 457-2310 (FAX)

Why was the data set created?

This GIS overlay, which is a component of the GIS database for NOAA Survey H11045 in the West-Central Basin of Long Island Sound, contains the completed sidescan sonar mosaic for the study area. The image is projected in UTM and has not been enhanced, inverted or cropped. Light tones represent relatively soft returns, lower backscatter, and generally finer sediments. Dark tones represent relatively harder returns, higher backscatter, and generally coarser grained sediments.

How was the data set created?

  1. From what previous works were the data drawn?

    h11045_1m.tif (source 1 of 1)
    National Oceanic and Atmospheric Administration, h11045_1m.tif.

    Original sidescan sonar mosaic created by National Oceanic and Atmospheric Administration (NOAA). This image is projected in UTM to maintain the aspect ratio.

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

    Date: 2004 (process 1 of 1)
    The sidescan sonar imagery contained in this report was produced from data collected during 2004 as part of NOAA survey H11045 aboard the NOAA Ship RUDE. The data for these surveys were acquired in XTF (extended Triton data format) using a Klein 5500 sidescan sonar tow fish set to sweep 100 m to either side of the ship's track. The Klein 5500 tow fish emits two 50°-wide beams tilted down 20° from horizontal, and transmits at 100 kHz. The sidescan snoar were digitally recorded in XTF format using an ISIS data acquisition software package. One digitally recorded, the XTF data were processed using CARIS SIPS.

    The sidescan sonar data were multiplexed and filtered to convert the data into the desired processing format and to remove speckle noise and corrected for slant-range distortions. The mosaic include the following standards: 1 meter resolution, image 'shine through' to account for areas of overlap, and auto contrast adjustment. The final image was projected in Universal Transverse Mercator to maintain the aspect ratio.

    Person who carried out this activity:

    Bryan Chaveau
    Atlantic Hydrographic Branch, National Ocean and Atmospheric Administration
    Field Support Liason
    Hydrographic Systems and Technology Program
    Norfolk, VA 23510

    (757) 441-6726 (voice)

    Data sources used in this process:
    • XTF sidescan sonar data

    Data sources produced in this process:

    • h11045_1m.tif
    • h11045_1m.tfw

  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?

    There are no attributes associated with a GEOTIFF image.

  2. How accurate are the geographic locations?

    Navigation was by differential GPS; positional accuracy to less than 10 m.

  3. How accurate are the heights or depths?

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

    All collected data were processed and used to generate the digital mosaic

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

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Public domain data are freely redistributable with proper metadata and source attribution. Please recognize the National Oceanic and Atmospheric Administration as the originator of this dataset.

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

    U.S. Geological Survey
    c/o Larry Poppe
    384 Woods Hole Rd.
    Woods Hole, MA 02543

    (508) 548-8700 x2314 (voice)
    (508) 457-2310 (FAX)

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


  3. What legal disclaimers am I supposed to read?

    Although this data set has been used by the USGS and NOAA, no warranty, expressed or implied, is made by the USGS or NOAA as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS or NOAA in the use of these data or related materials.

  4. How can I download or order the data?

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

    The user must have a program capable of reading and processing "geotiff" images.

Who wrote the metadata?

Last modified: 07-Nov-2005
Metadata author:
U.S. Geological Survey
c/o Elizabeth Beaulieu
Physical Science Lab Technician
384 Woods Hole Rd.
Woods Hole, MA 02543

(508) 548-8700 x2277 (voice)
(508) 457-2310 (FAX)

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

Generated by mp version 2.8.6 on Mon Nov 07 09:01:34 2005