MOSAIC7 - Composite sidescan-sonar mosaic collected by the U.S. Geological Survey offshore of the Chandeleur Islands, LA, 2007 (UTM Zone 16N GeoTIFF)

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Frequently anticipated questions:

What does this data set describe?

Title:
MOSAIC7 - Composite sidescan-sonar mosaic collected by the U.S. Geological Survey offshore of the Chandeleur Islands, LA, 2007 (UTM Zone 16N GeoTIFF)
Abstract:
In 2006 and 2007, the U.S. Geological Survey, in partnership with Louisiana Department of Natural Resources and the University of New Orleans, conducted geologic mapping to characterize the sea floor and shallow subsurface stratigraphy offshore of the Chandeleur Islands in Eastern Louisiana. The mapping was carried out during two cruises on the R/V Acadiana. Data were acquired with the following equipment: an SEA Ltd SwathPlus interferometric sonar (234 kHz), Klein 3000 dual frequency sidescan sonar, and an Edgetech 512i chirp subbottom profiling system. The long-term goal of this mapping effort is to produce high-quality geologic maps and geophysical interpretations that can be utilized to investigate the impact of Hurricane Katrina in 2005 and to identify sand resources within the region.
  1. How might this data set be cited?
    U.S. Geological Survey, 2009, MOSAIC7 - Composite sidescan-sonar mosaic collected by the U.S. Geological Survey offshore of the Chandeleur Islands, LA, 2007 (UTM Zone 16N GeoTIFF): Open-File Report 2008-1195, 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.

    Baldwin, Wayne E., Pendleton, Elizabeth A., and Twichell, David C., 2009, Geophysical Data from offshore of the Chandeleur Islands, Eastern Mississippi Delta: Open-File Report 2008-1195, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.085591
    East_Bounding_Coordinate: -88.928501
    North_Bounding_Coordinate: 29.589904
    South_Bounding_Coordinate: 29.466703
  3. What does it look like?
    http://pubs.usgs.gov/of/2008/1195/images/mosaic7.jpg (JPEG)
    grey scale image of sidescan-sonar mosaic
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 12-Jun-2007
    Ending_Date: 21-Jun-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 13400 x 15000 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 row and column
      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 1/298.257224.
  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 (0-255). 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)
    • U.S. Geological Survey
  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
    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 approximately 71 square-km of sidescan sonar data that were collected in 2007. These data are used to define the sea-floor morphology offshore of the Chandeleur Islands in Eastern Louisiana.

How was the data set created?

  1. From what previous works were the data drawn?
    raw sidescan data (source 1 of 1)
    U.S. Geological Survey, Unpublished material, Sidescan-sonar data collection.

    Type_of_Source_Media: disc
    Source_Contribution:
    Data acquisition at sea: These sidescan-sonar data were collected with a Klein 3000 dual frequency sidescan sonar towed 3 meters astern of the R/V Acadiana. These data were acquired using SonarPro Software (version: none) during a cruise in June 2007. Data were collected along tracklines spaced 100 to 125 m apart at a speed of 1.5 to 2.5 m/s. The dual frequencies of the sonar system are 100 and 500 kHz . Navigation was by means of differential GPS. All sidescan-sonar data were logged digitally at a sample rate resulting in a 0.18-m pixel size in the across-track direction and approximately 0.14-m in the along-track direction following the methodology outlined in Danforth and others (1991) and Danforth (1997).
  2. How were the data generated, processed, and modified?
    Date: 2007 (process 1 of 7)
    Within XSonar Software (version: none) a median filtering routine (Malinverno and others, 1990) was applied to the raw sidescan-sonar data (.xtf) to remove speckle noise; the filter was 6 pixels across track by 3 pixels along track. The data were further processed to correct for fish altitude, slant and beam artifacts, and then merged with the navigation (Danforth, 1997). These 2007 data were affected by port noise on the following days 20070610-20070619. XSonar was edited to reduce the port highpass value (from 4095 to 2500), in an effort to improve the sonar image. Odd and even sidescan sonar lines were mapped seperately out of XSonar at 1 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

    (508) 548-8700x2259 (voice)
    (508) 457-2310 (FAX)
    ependleton@usgs.gov
    Date: 2007 (process 2 of 7)
    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 1 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

    (508) 548-8700x2259 (voice)
    (508) 457-2310 (FAX)
    ependleton@usgs.gov
    Data sources used in this process:
    • MOSAIC9.pix
    Data sources produced in this process:
    • MOSAIC9.tif
    Date: Unknown (process 3 of 7)
    The days that experienced portside noise problems (20070610-20070619) needed further processing to improve the mosaic image. Portside swaths that displayed as 'whiteout' within the mosaicked image had pixel values greater than 200 (out of 256) due to noise, and were deleted using the lasso tool in Adobe Photoshop CS2 (version 9.0.2). Person who carried out this activity:
    Elizabeth A. Pendleton
    U.S. Geological Survey
    Geologsit
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700x2259 (voice)
    (508) 457-2310 (FAX)
    ependleton@usgs.gov
    Date: 03-Nov-2016 (process 4 of 7)
    Edits to the metadata were made to fix any errors that MP v 2.9.34 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The source information was incomplete and had to be modified to meet the standard. Formatting of the cross-references was fixed to meet the metadata standard. Some online links were added to the cross-references. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent. 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)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 5 of 7)
    USGS Thesaurus keywords added to the keyword section. 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)
    vatnipp@usgs.gov
    Date: 18-Nov-2019 (process 6 of 7)
    Crossref DOI link was added as the first link in the metadata. 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)
    vatnipp@usgs.gov
    Date: 08-Sep-2020 (process 7 of 7)
    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)
    vatnipp@usgs.gov
  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 Jan. 1991.

    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, Reston, VA.

    Online Links:

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

    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, Reston, VA.

    Online Links:

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?
    These data were navigated with a Differential Global Positioning System (DGPS) mounted above the interferometric sonar head. Unless noted, all DGPS data are referenced to WGS84. The layback distance between towed sidescan sonar fish and the mounted GPS antennae were measured on the ship and corrected for these navigation data.
  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. Some lines with excess noise were clipped after the mosaic was completed.
  5. How consistent are the relationships among the observations, including topology?
    Information unavailable from original metadata.

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)
    Wayne E. Baldwin
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700x2226 (voice)
    (508) 457-2310 (FAX)
    wbaldwin@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?
    • Availability in digital form:
      Data format: This WinZip (version 9.0) file contains a geographic GeoTIFF image of side-scan sonar data collected offshore of the Chandeleur Islands, LA, and associated metadata. in format GeoTIFF (version PCI version 10.1) Size: 37.9
      Network links: http://pubs.usgs.gov/of/2008/1195/GIS_catalog/Sidescan/mosaic7.zip
      Media you can order: DVD-ROM (Density 4.75 Gbytes) (format UDF)
    • Cost to order the data: none

  5. What hardware or software do I need in order to use the data set?
    This zip file contains a GeoTIFF image with an accompanying world file. To utilize this 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-Mar-2024
Metadata author:
Elizabeth A. Pendleton
U.S. Geological Survey
Geologist
384 Woods Hole Rd.
Woods Hole, MA

(508) 548-8700x2259 (voice)
(508) 457-2310 (FAX)
whsc_data_contact@usgs.gov
Contact_Instructions:
The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240318)
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/open_file_report/ofr2008-1195/mosaic7.tif.faq.html>
Generated by mp version 2.9.51 on Mon Mar 25 16:05:26 2024