Nahant to Gloucester, 1m resolution Sidescan Sonar Mosaic (SS_MOS1M.TIF)

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Frequently anticipated questions:


What does this data set describe?

Title:
Nahant to Gloucester, 1m resolution Sidescan Sonar Mosaic (SS_MOS1M.TIF)
Abstract:
These data are high-resolution acoustic backscatter measurements of the seafloor offshore of Massachusetts, from Nahant to Gloucester. Approximately 127 km2 of the inner shelf were mapped in the nearshore region between the 10m and 40-m isobath.
  1. How might this data set be cited?
    Andrews, Brian D., 2005, Nahant to Gloucester, 1m resolution Sidescan Sonar Mosaic (SS_MOS1M.TIF): Open File Report 2005-1293, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Barnhardt, Walter A., Andrews, Brian D., and Butman, Bradford, 2006, High-Resolution Mapping of the Inner Continental Shelf: Nahant to Gloucester, Massachusetts: Open-File Report 2005-1293, U.S. Geological Survey, Reston, VA.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.942180
    East_Bounding_Coordinate: -70.660046
    North_Bounding_Coordinate: 42.577803
    South_Bounding_Coordinate: 42.388418
  3. What does it look like?
    http://coastalmap.marine.usgs.gov/GISdata/regional/eastcoast/gome/nahant-gloucester/sidescan/ss_mos1m-thumb.gif (GIF)
    Thumbnail image showing the extent and coverage of the data layer.
    http://coastalmap.marine.usgs.gov/GISdata/regional/eastcoast/gome/nahant-gloucester/sidescan/ss_mos1m.gif (GIF)
    Overview image showing the extent and coverage of the data layer.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 22-Sep-2003
    Ending_Date: 07-May-2004
    Currentness_Reference:
    ground condition of two separate date ranges - 20030922 to 20031015 and 20040412 to 20040507
  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 20556 x 22763 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 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?
    Band_1
    Information unavailable from original metadata. (Source: Information unavailable from original metadata.)
    ObjectID
    Internal feature number. (Source: ESRI) Sequential unique whole numbers that are automatically generated.
    Entity_and_Attribute_Overview: There are no attributes associated with the GeoTIFF image.
    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)
    • Brian D. Andrews
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Brian Andrews
    U.S. Geological Survey
    Marine Geographer
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
    508-457-2310 (FAX)
    bandrews@usgs.gov

Why was the data set created?

These data were collected under a cooperative agreement with the Massachusetts Office of Coastal Zone Management (CZM) and the U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center. High resolution bathymetry, backscatter intensity, and seismic profile data were collected over 127 km2 area covering a portion of the South Essex Ocean Sanctuary to characterize the surface and subsurface of the seafloor for regional geologic framework investigations. Backscatter data were collected during two different surveys. Survey RAFA03007 began Monday, 22 Sep 2003 (JD267) and ended on Tuesday, 14 Oct 2003 (JD287). RAFA04002 began 17 Apr 2004 (JD 108) and ended on 2 May 2004 (JD123).

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: unknown (process 1 of 7)
    Sidescan data were acquired with Edgetech DF-1000, dual frequency towed sidescan sonar with average layback of Collected with 150m range layback = 6 meters
    Date: unknown (process 2 of 7)
    raw .xtf data were processed and corrected for slant range corrections in XSONAR/SHOWIMAGE
    Date: unknown (process 3 of 7)
    the Xsonar files were mosaiced in Xsonar and then exported to PCI Geomatica as raw files
    Date: unknown (process 4 of 7)
    PCI Geomatica mosaiced individual line files and georeferenced to UTM Z 19
    Date: unknown (process 5 of 7)
    The positional accuracy of the final 1m resolution mosaic was increased by further georeferrencing (rubber sheeting) to the submetrix interferometric sonar backscatter mosaic. The interferometric data has higher order positional accuracy than the towed sidescan-sonar because the GPS antenna is mounted on top of the same pole as the interferometric sonar and there is no inacuracies from towfish layback. The rubber sheeting was calculated in ArcGIS with the Georefferencing.
    Date: 18-Nov-2015 (process 6 of 7)
    Edits to the metadata were made to fix any errors that MP v 2.9.30 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.). Online linkages were fixed (some needed to point to pubs.usgs.gov). None of the original process steps had process dates, so those were set to "unknown". Time period of content date format was fixed. 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 Rd.
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 20-Jul-2018 (process 7 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
  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?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
    The RTK corrected signal was sent from a USGS survey-specific base station at the lighthouse on Eastern Point Lighthouse. The base station occupied a DMA monument, however, the x, & y positions were calculated for that location using a 3 day average of 12 hour data sets using the Online Positioning User Service (OPUS, National Geodetic Survey) solution. Sidescan tow fish layback was 6 meters.
  4. Where are the gaps in the data? What is missing?
    Information unavailable from original metadata.
  5. How consistent are the relationships among the observations, including topology?
    These data have not been quantitatively compared to previous hydrographic data, although they generally agree with qualitative comparison of published NOAA charts.

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 (USGS) as the source of this information.
  1. Who distributes the data set? (Distributor 1 of 1)
    Brian Andrews
    U.S. Geological Survey, Woods Hole Science Center
    Marine Geographer
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    508-548-8700 x2348 (voice)
  2. What's the catalog number I need to order this data set? Downloadable Data
  3. What legal disclaimers am I supposed to read?
    Although this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS 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 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 image is available as 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: 20-Jul-2018
Metadata author:
Brian Andrews
U.S. Geological Survey
Marine Geographer
384 Woods Hole Rd.
Woods Hole, MA
USA

508-548-8700 x2348 (voice)
508-457-2310 (FAX)
bandrews@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/eastcoast/gome/nahant-gloucester/ss_mos1m.tif.faq.html>
Generated by mp version 2.9.49 on Mon Sep 10 17:45:06 2018