SONAR_05M_STR.TIF: Sidescan-sonar mosaic, with linear stretch applied, collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, MA, 2007. (GeoTIFF IMAGE)

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Frequently-anticipated questions:

What does this data set describe?

Title:
SONAR_05M_STR.TIF: Sidescan-sonar mosaic, with linear stretch applied, collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, MA, 2007. (GeoTIFF IMAGE)
Abstract:
The USGS Woods Hole Science Center conducted a nearshore geophysical survey offshore of the southern coast of Martha's Vineyard, in the vicinity of the Martha's Vineyard Coastal Observatory (MVCO) in August 2007. This mapping program was part of a larger research effort supporting the Office of Naval Research (ONR) Ripples Directed-Research Initiative (DRI) studies at MVCO by providing data collection and modeling. The geophysical data will be used to provide initial conditions for wave and circulation models for the study area. Ultimately, geophysical mapping, oceanographic measurements and modeling will help to improve our understanding of coastal sediment-transport processes.

The geophysical mapping utilized a suite of high-resolution instrumentation to map the surficial sediment distribution, depth and sub-surface geology: dual-frequency 100/500 KHz sidescan-sonar system, 234-KHz interferometric sonar, and 500 Hz -12 KHz chirp sub-bottom profiler. The survey was conducted aboard the M/V Megan Miller August 9-13, 2007. The study area covers 35 square kilometers from about 0.2 km to 5-km offshore of the south shore of Martha's Vineyard, and ranges in depth from ~ 5 to 20 meters.

  1. How should this data set be cited?

    U.S. Geological Survey, 2009, SONAR_05M_STR.TIF: Sidescan-sonar mosaic, with linear stretch applied, collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, MA, 2007. (GeoTIFF IMAGE): Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.

    Online Links:

    This is part of the following larger work.

    Denny, J.F., Danforth, W.W., Foster, D.S., and Sherwood, C.R., 2009, Geophysical Data Collected off the South Shore of Martha's Vineyard, Massachusetts: Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -70.606602
    East_Bounding_Coordinate: -70.509756
    North_Bounding_Coordinate: 41.352586
    South_Bounding_Coordinate: 41.297266

  3. What does it look like?

    <https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Sonar/sonar_05m_str_sm.jpg> (JPEG)
    Thumbnail image of sidescan-sonar data collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, 2007

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

    Beginning_Date: 09-Aug-2007
    Ending_Date: 13-Aug-2007
    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 12000 x 16000 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?

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?

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

Why was the data set created?

The sidescan-sonar mosaic will be used to identify bedforms and surficial sediment distribution in the vicinity of the Martha's Vineyard Coastal Observatory. The composite image will also be used as a base map for divers to collect sediment cores at fine and coarse sand boundaries prior to placement of oceanographic instruments.

Applying a fixed linear stretch to the sidescan-sonar data provides a TIF image with an increased dynamic range to highlight features (i.e. bedforms) on the seafloor.

How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    .

    Source_Contribution:
    Data were acquired with an L3-Klein Associates 3000 digital, dual-frequency, sidescan-sonar (www.l-3klein.com). Dual frequencies are nominally 100 (132 kHz) and 500 (445 kHz) kHz. The sidescan-sonar was towed aft of the R/V Megan Miller. A digital cable-out display was used to measure tow-fish layback. Layback and DGPS input were used by the SonarPro acquisition software to calculate position of the sonar tow-fish and store in the raw data files. Line spacing varied from 40 meter in ~ 5 to 15 meter water depth to 75 meters in ~15 - 25 meter water depth. Data files were recorded with SonarPro 10.0 in XTF (extended-Triton Format) format at a 0.03-sec ping rate yielding a 50-meter range (100-meter swath). The 100 kHz data were used to generate the sidescan-sonar mosaic. The data range within the sidescan-sonar mosaic (digital number values (DN) of the 8-bit image) is 0 - 250, with the background value (i.e. No DATA) set to 255.

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

    Date: 2008 (process 1 of 4)
    XSonar/ShowImage (no version) sidescan-sonar processing software (version: none) was used to process the raw XTF sonar data following the methodology of Danforth, (1997). A 4 across track x 3 along track pixel median filter was applied to the raw sidescan-sonar data to remove speckle noise and a normalization of 4095 was applied to adjust the dynamic range within the output processed file. Processed data are stored as 8-bit. Navigation were also extracted from the raw data at a 1-minute interval and saved in ASCII file. Quality checks were conducted on the navigation to eliminate spurious or duplicate navigation fixes. The sonar data were further processed to correct for towfish altitude (i.e. proper tracking of the seafloor), and slant-range and beam pattern distortions inherent in the sonar data. Processed sonar files were then merged with the edited navigation. Processed sonar files were then mapped at a 0.5-meter resolution in UTM coordinates (UTM, Zone 19N, WGS84, meters) and saved in two XSonar/ShowImage mosaic files representing odd and even (i.e. every other line) sonar tracklines, or files.

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

    Date: 2008 (process 2 of 4)
    The Unix Portable Bitmap Format (PBM) utilities, rawtopgm and pnmtotiff, were used to extract the 80-byte header from the XSonar/ShowImage odd and even mosaic files and convert the raw raster image to a TIFF image file. (rawtopgm -headership 80 #xpixel #ypixel *.ras | pnmtotiff - > *.tif)

    Software: PBM utilities (1x)

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

    Date: 2008 (process 3 of 4)
    The odd and even tiff images were then imported into PCI Geomatica Software (version 10.1) and digitally mosaicked at a 0.5-meter pixel resolution using PCI's OrthoEngine based on the procedures described in Paskevich (1996). The composite mosaic was registered in the UTM (Zone 19N, WGS84, meters) coordinate system and exported as a GeoTIFF image with ESRI world file in case the GeoTIFF cannot be read.

    Software: PCI Geomatica (10.1)

    Date: 2008 (process 4 of 4)
    The TIFF image was then imported to Adobe Photoshop CS3 in order to adjust the 8-bit range of the image file, so that areas of no data (i.e. the background) are represented by a pixel value of 255 and areas of data range from pixel values of 0 to 250. The 'color range' tool, under the 'Select' menu was used to isolate areas of no data. The 'inverse' tool was then used to isolate areas of data.

    A linear stretch was then applied using 'Images, Adjustments, Levels' tools to the data to increase the dynamic range, mapping input values of 0 to 100 to a range of 0 to 250.

    Software: Adobe Photoshop CS3 (10.0.1)

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@usgs.gov

    Data sources used in this process:
    • sonar_05m.tif

    Data sources produced in this process:

    • sonar_05m_str.tif

  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: Sea Technology January 1991, Sea Technology, Woods Hole, MA.

    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.

    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?

    Differential Global Positioning System (DGPS) navigation data were acquired with a LGBX Pro receiver and sent directly to the sidescan-sonar acquisition software, L3-Klein Associates, SonarPro. The LGBX Pro received DGPS positions from a DGPS antenna located on the starboard, aft roof of the acquisition van. The layback of the sidescan-sonar towfish was measured with a digital block cable counter. The cable counter data were sent directly to SonarPro as a serial string. SonarPro computes the actual tow-fish position using the DGPS input and the layback. The following offsets are measured prior to deployment of the sidescan-sonar tow-fish and entered into SonarPro: height of the block, offset from DGPS antenna to the block, and height of the DGPS antenna above the waterline. Prior to deploying the sidescan-sonar tow-fish, the tow-fish is hauled to the block in order to zero the cable counter. DGPS accuracy is 1 to 3 meters, depending on the distance from a US Coast Guard coastal repeater station (<http://www.navcen.uscg.gov/>).

  3. How accurate are the heights or depths?

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

    All available data were used to create the backscatter mosaic. Sidescan-soar data were collected along shore-parallel tracklines. Sonar data were not acquired along shore-perpendicular tie lines. Data gaps within the sidescan-sonar image correspond to slight course change to steer around MVCO 12-meter node and ASIT. Additional gaps are due to obstacle avoidance and removal of poor quality data during QC (e.g. 100 meter data gap between tracklines 4 and 6).

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

    All sidescan-sonar data were collected with a Klein dual-frequency sidescan-sonar system. The 100-kHz data were used to generate the sidescan-sonar mosaic. Quality control during data processing minimized any data inconsistencies and/or anomalies. All data were processed with a similar methodology.

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)

    Jane Denny
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA 02543-1598

    (508) 548-8700x2311 (voice)
    5084572310 (FAX)
    jdenny@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 USGS 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 and world file. 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: 04-Oct-2009
Metadata author:
Jane Denny
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA 02543-1598

(508) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@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 Sun Oct 04 15:44:27 2009