COMP2M_GEO: Composite 2-m Bathymetric ArcRaster Grid of National Oceanic and Atmospheric Administration (NOAA) Surveys H11252 and H11361 from Eastern Long Island Sound (Geographic)

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Frequently-anticipated questions:


What does this data set describe?

Title:
COMP2M_GEO: Composite 2-m Bathymetric ArcRaster Grid of National Oceanic and Atmospheric Administration (NOAA) Surveys H11252 and H11361 from Eastern Long Island Sound (Geographic)
Abstract:
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 multibeam bathymetric data within specific areas of special interest. The composite bathymetric grid in Geographic presented herein covers a roughly 156 km square area (surveys H11252 and H11361) of the sea floor in the area near Six Mile Reef, eastern Long Island Sound. The original multibeam bathymetric data were collected during 2004 as part of charting applications aboard the NOAA Survey Vessel Thomas Jefferson. A Simrad EM1002 multibeam system mounted on the hull of this vessel was used to acquire data along survey lines from the deeper water (>20 m) parts of the survey areas. Two 29-foot launches with hull-mounted Reson systems were deployed from the ship and were used to acquire data along survey lines from the shallower areas.

Detailed bathymetric data 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 bathymetric data models 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?

    U.S. Geological Survey, 2007, COMP2M_GEO: Composite 2-m Bathymetric ArcRaster Grid of National Oceanic and Atmospheric Administration (NOAA) Surveys H11252 and H11361 from Eastern Long Island Sound (Geographic): Open-File Report 2007-1191, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Poppe, L.J., Denny, J.F., Williams, S.J., Moser, M.S., Forfinski, N.A., Stewart, H.F., and Doran, E.F., 2007, The Geology of Six Mile Reef, Eastern Long Island Sound: Open-File Report 2007-1191, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details: 1 DVD-ROM

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -72.658359
    East_Bounding_Coordinate: -72.393357
    North_Bounding_Coordinate: 41.226032
    South_Bounding_Coordinate: 41.143008

  3. What does it look like?

    <http://pubs.usgs.gov/of/2007/1191/data/composite/bathy/grids/geo/comp2m_geo.gif> (GIF)
    Thumbnail image showing the composite 2-m bathymetric grid from NOAA surveys H11252 and H11361 in Geographic.

  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: raster digital data

  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 4618 x 14740 x 1, type Grid Cell

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

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees.

      The horizontal datum used is North American Datum of 1983.
      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.

      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:

  7. How does the data set describe geographic features?

    comp2m_geo

    ObjectID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Value


    Count



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?

    Source data were acquired during National Oceanic and Atmospheric Administration (NOAA) surveys H11252 and H11361 aboard the survey vessel Thomas Jefferson. Please acknowledge NOAA as the originator of the dataset from which this dataset was derived.

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

    Larry Poppe
    U.S. Geological Survey
    Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598
    USA

    508-548-8700 x2314 (voice)
    508-457-2310 (FAX)
    lpoppe@usgs.gov


Why was the data set created?

To release a composite 2-m bathymetric ArcRaster grid generated from NOAA surveys H11252 and H11361 in Geographic


How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Type_of_Source_Media: DVD-ROM
    Source_Contribution:
    The original multibeam bathymetric data acquired with Simrad EM1002, Reson 8101, and 8125 echosounder systems during NOAA surveys H11252 and H11361 aboard the NOAA ship Thomas Jefferson. A Simrad EM1002 multibeam system mounted on the hull of this vessel was used to acquire data along survey lines from the deeper water (>20 m) parts of the survey areas. Two 29-foot launches with hull-mounted Reson systems were deployed from the ship and were used to acquire data along survey lines from the shallower areas.

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

    (process 1 of 3)
    The multibeam data were acquired in XTF (extended Triton data format), recorded digitally through an ISIS data acquisition system, and processed using CARIS HIPS (Hydrographic Image Processing System) software for quality control, to incorporate sound velocity and tidal corrections, and to produce base surfaces averaging 2-m resolution over the study area. The raw bathymetric data were exported in ASCII text format in UTM Zone 18.

    Person who carried out this activity:

    Marc Moser
    National Oceanic and Atmospheric Administration
    Field Operations Officer
    439 West York Street
    Norfolk, VA 23510
    USA

    757-441-6726 (voice)
    marc.s.moser@noaa.gov

    Data sources used in this process:
    • raw bathymetric data

    Data sources produced in this process:

    • h11252_2mutm18_xyz.txt
    • h11361_2mutm18_xyz.txt

    Date: 2007 (process 2 of 3)
    The xyz (easting, northing, and depth) data were combined using the University of New Brunswick SwathEd weigh_grid command. The composite grid created in SwathEd was then imported into IVS Fledermaus (DMagic). Data were then exported as an ESRI Grid file using IVS DMagic Export Surface.

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    GIS Specialist
    384 Woods Hole Road
    Woods Hole, MA 02543

    508-548-8700 x2311 (voice)
    508-457-2310 (FAX)
    jdenny@usgs.gov

    Data sources used in this process:
    • h11252_2mutm18_xyz.txt
    • h11361_2mutm18_xyz.txt

    Data sources produced in this process:

    • comp2m_utm

    (process 3 of 3)
    ESRI "Project Raster" was used to convert the grid from UTM Zone 18 to Geographic.

    Person who carried out this activity:

    Jane Denny
    U.S. Geological Survey
    GIS Specialist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598

    508-548-8700 x2311 (voice)
    508-457-2310 (FAX)
    jdenny@usgs.gov

    Data sources used in this process:
    • comp2m_utm

    Data sources produced in this process:

    • comp2m_geo

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

    Poppe, L.J., Williams, S.J., Moser, M.S., Forfinski, N.A., Stewart, H.F., and Doran, E.F., 2007, Quaternary geology and sedimentary processes in the vicinity of Six Mile Reef, eastern Long Island Sound: Journal of Coastal Research v. 23, no. 6.


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?

    Navigation was by differential GPS. Horizontal resolution of the data varies with water depth, but averages 2 m.

  3. How accurate are the heights or depths?

    Vertical resolution is about 0.5% of the water depth.

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

    All collected data were processed and used to produce this dataset.

  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
Use_Constraints:
Public domain data are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) and the Connecticut Department of Environmental Protection (CTDEP) as the originators of this data set.

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

    U.S. Geological Survey
    c/o Larry Poppe
    Geologist
    384 Woods Hole Road
    Woods Hole, MA 02543-1598

    508-548-8700 x2314 (voice)
    508-457-2310 (FAX)
    lpoppe@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?

    Although this data set has been used by the U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), and the Connecticut Department of Environmental Protection (CTDEP), no warranty, expressed or implied, is made by the USGS, NOAA, and the Connecticut DEP 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 these agencies 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?

    These data are available in Environmental Systems Research Institute (ESRI) Raster GRID format. The user must have software capable of importing and processing the data files.


Who wrote the metadata?

Dates:
Last modified: 17-Aug-2007
Metadata author:
U.S. Geological Survey
c/o Larry Poppe
Geologist
384 Woods Hole Road
Woods Hole, MA 02543-1598
USA

508-548-8700 x2314 (voice)
508-457-2310 (FAX)
lpoppe@usgs.gov

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


Generated by mp version 2.8.6 on Fri Aug 17 08:23:11 2007