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Connecticut Eelgrass Beds 2009 Poly

Frequently-asked questions:

What does this data set describe?

Connecticut Eelgrass Beds 2009 Poly

This data layer was created by the Conservation Management Institute, Virginia Tech University for the USFWS National Wetlands Inventory, Region 5. The project area encompasses the eastern end of Long Island Sound, including Fishers Island and the North Fork of Long Island. It includes all coastal embayments and nearshore waters (i.e., to a depth of -15 feet at mean low water) bordering the Sound from Clinton Harbor in the west to the Rhode Island border in the east and including Fishers Island and the North Shore of Long Island from Southold to Orient Point and Plum Island. The study area includes the tidal zone of 18 sub-basins in Connecticut: Little Narragansett Bay, Stonington Harbor, Quiambog Cove, Mystic Harbor, Palmer-West Cove, Mumford Cove, Paquonock River, New London Harbor, Goshen Cove, Jordan Cove, Niantic Bay, Rocky Neck State Park, Old Lyme Shores, Connecticut River, Willard Bay, Westbrook Harbor, Duck Island Roads, and Clinton Harbor, and two areas in New York: Fishers Island and a portion of the North Shore of Long Island. Delineations of 2009 eelgrass beds were completed using 1:20,000 true color aerial photography flown at low tide on 7/14/2009 and 7/15/2009. Extensive field work was conducted by the USFWS Region 5 Southern New England-New York Bight Coastal Program Office in October, November, and December 2009 with 193 field sites checked. The 2009 photography was scanned and geo-rectified using 2006 NAIP 1 meter true color imagery.

Data have been summarized in a technical report: Tiner, R., K. McGuckin, M. Fields, N. Fuhrman, T. Halavik, and A. MacLachlan. 2010. 2009 Eelgrass Survey for Eastern Long Island Sound, Connecticut and New York. U.S. Fish and Wildlife Service, National Wetlands Inventory Program, Northeast Region, Hadley, MA. National Wetlands Inventory report. 16 pp. plus Appendix.

  1. How should this data set be cited?

    USFWS NWI Region 5, Unknown, Connecticut Eelgrass Beds 2009 Poly.

    Online links:
  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -72.483018
    East: -71.856998
    North: 41.349679
    South: 41.152131

  3. What does it look like?

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

    Calendar date: 7/14/09
    Calendar date: 7/15/09
    Currentness reference:
    ground condition

  5. What is the general form of this data set?

    Geospatial data presentation form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (172)

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

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Lambert Conformal Conic
      Standard parallel: 41.200000
      Standard parallel: 41.866667
      Longitude of central meridian: -72.750000
      Latitude of projection origin: 40.833333
      False easting: 999999.999996
      False northing: 499999.999998

      Planar coordinates are encoded using coordinate pair.
      Abscissae (x-coordinates) are specified to the nearest 0.000328.
      Ordinates (y-coordinates) are specified to the nearest 0.000328.
      Planar coordinates are specified in survey feet.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical coordinate system definition:
      Altitude system definition:
      Altitude resolution: 1.000000
      Altitude encoding method: Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

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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?

    Ralph Tiner
    U.S. Fish & Wildlife Service, Northeast Region
    National Wetlands Inventory, R5 Coordinator
    300 Westgate Center Drive
    Hadley, Massachusetts 01035

    413-253-8620 (voice)
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Why was the data set created?

This dataset was developed for an ongoing eelgrass monitoring of the Long Island Sound.  Funding was provided by the EPA, Region 2. 

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How was the data set created?

  1. Where did the data come from?

    Type of source media: True Color photography
    Source scale denominator: 1:20,000
    Source contribution:
    Sames W. Sewall 
    136 Center Street, P.O. Box 433 
    Old Town, Maine 04468-0433 
    207 827 4456
    fax: 207 827 3641

  2. What changes have been made?

    Date: Sept '09 - May '10 (change 1 of 5)
    The 2009, 1:20000 true color photography was scanned and geo-rectified in ArcGIS 9.3 to NAIP 2006 true color 1 meter resolution imagery for Connecticut and New York. The 2006 eelgrass datalayer was used as a base, and polygonal data was added, subtracted or adjusted to reflect what was identified on the newer imagery. Field work was completed using a USFWS research vessel, and USFWS personnel. One Hundred Ninety Three sites were checked and documented. This information was converted to a point datalayer and used to adjust the original delineation.  In some cases, very small beds that were identified during the field survey were mapped as points and buffered to yield a polygon of 0.1-acre in size. Bed density was determined using spectral signatures in the current imagery.  2006 and 2002 surveys and field observations were used to help identify these signatures in the initial drafts.  Field observations from 2009 were then incorporated into the final revision and took precedence over previous density identifications.  The interpretations were then displayed in map form using the 2009 digital imagery as the base map.

    Date: 20100430 (change 2 of 5)
    Dataset copied.

    Data sources used in this process:
    • \\FT-CUBEQ-KEVIN\E$\NWI\Eelgrass\Eelgrass_20091002_Final.mdb

    Date: 20100503 (change 3 of 5)
    Dataset copied.

    Data sources used in this process:
    • \\FT-CUBEQ-KEVIN\E$\NWI\Eelgrass\Eelgrass_20091005_Draft.mdb

    Date: 20101108 (change 4 of 5)
    Dataset copied.

    Data sources used in this process:
    • \\depnb100\Data\GIS\Workspaces\Coastal\KOB\Eelgrass\Eelgrass_Final_20100603\Eelgrass_2009_CT_St_Plane.mdb

    Date: 20101209 (change 5 of 5)
    Metadata imported.

    Data sources used in this process:
    • C:\Trash\EELGRASS_BEDS_2009_POLY1.xml

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How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    Attribute accuracy  based on quality of 1:20000 photography, and the ability to indentify submerged vegetation and the density of beds.

  2. How accurate are the geographic locations?

    Based on photography, and the abiltiy to identify eelgrass beds and delineate them from 1:20,000 True Color geo-rectified photography

  3. How accurate are the heights or depths?

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

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

    Photography was taken during two flgiht missions on July 14, 2009 and July 15, 2009, at low tide.

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How can someone get a copy of the data set?

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

Access constraints: no known access retrictions
Use constraints:
contraints based on limitation of methods of aquiring data through remotely sensed processes.

Distributor 1 of 1

  1. Who distributes the data set?

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

    Connecticut Eelgrass Beds 2009 Poly

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?

    • Availability in digital form:

    • Data format:
      Size: 0.157

  5. Is there some other way to get the data?

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

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Who wrote the metadata?

Last modified: 20120119

Metadata author:
Kevin McGuckin
Consevation Management Institute
GIS Manager
1900 Kraft Dr. Suite 250
Blacksburg, VA 24061

540-231-9197 (voice)

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

Metadata extensions used:
  • http://www.esri.com/metadata/esriprof80.html

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