Dr. Charles Yarish, University of Connecticut Dept. of Ecology and Evolutionary Biology (compiler)
Mary DiGiacomo-Cohen, Long Island Sound Resource Center (editor)
State of Connecticut, Department of Environmental Protection (publisher)
1997
Observed Eelgrass Beds
vector digital data
Hartford, Connecticut, USA
State of Connecticut, Department of Environmental Protection
This layer is not updated and does not represent current conditions.
http://www.ct.gov/deep
Observed Eelgrass Beds is a 1:24,000 scale, polygon feature-based layer that depicts the locations of observed eelgrass beds in Long Island Sound, in major rivers, and within bays, harbors and other waterbodies along Connecticut's coast. The layer is based on information from the Eelgrass Sample Points layer. It represents conditions at a particular point in time (1993 to 1995). During the 1993-95 field seasons a team of researchers from the University of Connecticut Dept. of Ecology and Evolutionary Biology led by Charles Yarish, equipped with a Global Positioning System (GPS), SCUBA, and a 20' boat surveyed over 800 potential eelgrass locations. Their GPS coordinates and field notes were used to create a point coverage entitled Eelgrass Sample Points, which was plotted and checked on a 1:24000 scale base map of the Connecticut shore. These point locations, observations, and the nearshore bathymetry were then used to delineate areas representing both observed and potential eelgrass beds. Eelgrass beds were initially digitized at 1:24,000 scale, but have been edited and revised on screen at higher resolution. Keeping in mind the temporal and spatial variability of eelgrass, beds may vary in size, shape, and density from year to year.
Feature locations may not always be exact due to equipment failure or lack of satellite reception. In those cases, points were estimated from field notes. It should be noted that the Observed Eelgrass Beds layer is not a complete dataset of all observed eelgrass sites in Connecticut and/or Long Island Sound. This layer was published in 1997 and is not updated. It does not represent current conditions.
There are 101 polygon features representing observed eelgrass beds in this layer. Geographic locations are as follows: westernmost areas: Clinton Harbor; easternmost areas: Little Narragansett Bay, Rhode Island waters. Observed beds range in size from .003 acre (131 sq. ft.) to 49 acres (2,136,608 sq. ft.). The total area of observed beds is 632.6 acres.
Observed Eelgrass Beds is 1:24,000-scale data. The purpose of this datalayer is to depict the locations of observed eelgrass along Connecticut's coast. The polygons in this layer were created from the Eelgrass Sample Points layer. This layer is not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)
For more information, refer to the Eelgrass Sample Points and Potential Eelgrass Beds layers.
1993
1995
ground condition
None planned
-72.540127
-71.872764
41.368846
41.254379
None
Eelgrass
Observed Eelgrass
None
Long Island Sound
Connecticut River
Little Narragansett Bay
U.S. Department of Commerce, 1987, Codes for the Identification of the States, the District of Columbia and the Outlying Areas of The United States, and Associated Areas (Federal Information Processing Standard 5-2): Washington, DC, National Institute of Standards and Technology.
Connecticut
CT
Rhode Island
RI
U.S. Department of Commerce, 1995, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions (Federal Information Processing Standard (FIPS) 10-4): Washington, D.C., National Institute of Standards and Technology.
United States of Connecticut
USA
None. The data is in the public domain and may be redistributed.
None. No restrictions or legal prerequisites for using the data. Note, the data is not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.) Once acquired, any modification made to the data must be noted in the metadata. When printing this information on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Department of Environmental Protection as the source for this information.
State of Connecticut, Department of Environmental Protection
Kevin O'Brien
mailing and physical address
79 Elm Street
Hartford
Connecticut
06106-5127
USA
860-424-3034
860-424-4054
dep.gisdata@ct.gov
Monday to Friday, 08:30 to 16:30 Eastern Standard Time
http://www.cteco.uconn.edu/metadata/dep/browsegraphic/eelgrassbedobpotfullview.gif
Full view of Observed and Potential Eelgrass Beds 1993-1995
GIF
http://www.cteco.uconn.edu/metadata/dep/browsegraphic/eelgrassbedobpotdetailview.gif
Detail view of Observed and Potential Eelgrass Beds 1993-1995
GIF
These data are maintained by the State of Connecticut using ArcGIS software developed by Environmental Systems Research Institute (ESRI) in a Microsoft Windows operating system environment.
Attribute accuracy is unknown.
Logical consistency for this layer is not known.
The completeness of the data reflects the feature content of the data sources, which includes the GPS data files and field notes. This layer is complete in the sense that it accurately reflects the contents of the above referenced source information available at the time the State of Connecticut, Department of Environmental Protection created the layer. However, compared to current conditions, this layer is incomplete and is not updated.
The horizontal positional accuracy of this data is unknown.
State of Connecticut, Department of Environmental Protection
University of Connecticut, Long Island Sound Resource Center
1997
Eelgrass Sample Points
vector digital data
http://www.ct.gov/deep
24000
disc
1997
publication date
Source 1 - Eelgrass Sample Points Coverage
This source served as the major source of base data for the creation of Observed Eelgrass Beds. GPS coordinates and field notes were used to create the Eelgrass Sample Points coverage, which was plotted and checked on a 1:24000 scale base map of the Connecticut shore. These point locations, observations, and the nearshore bathymetry were then used to delineate areas representing both observed and potential eelgrass beds.
State of Connecticut, Department of Environmental Protection
University of Connecticut, Long Island Sound Resource Center
1997
Observed Eelgrass Beds Coverage
vector digital data
http://www.ct.gov/deep
24000
disc
1997
publication date
Source 2 - Observed Eelgrass Beds Coverage
This data source refers to all features combined in one statewide layer. Since initial publication in 1997, subsequent publication of the layer was generated by the State of Connecticut in order to convert from NAD 27 to NAD 83. Consequently, a different copy of this layer was produced, representing the change in the state plane coordinate system. Changes made to the entire layer are reflected in metadata process steps where this particular data source is cited as both the Source Used and the Source Produced.
State of Connecticut, Department of Environmental Protection
1997
Observed Eelgrass Beds Shapefile
vector digital data
http://www.ct.gov/deep
24000
disc
1997
publication date
Source 3 - Observed Eelgrass Beds Shapefile
This source represents the final form of Observed Eelgrass Beds and was produced from the Observed Eelgrass Beds ArcInfo Coverage.
Feature Creation and Attribution - During the 1993-95 field seasons a team of researchers led by Charles Yarish, equipped with a Global Positioning System (GPS), SCUBA, and a 20' boat surveyed over 800 potential eelgrass locations. Their GPS coordinates and field notes were used to create a point coverage entitled Eelgrass Sample Points (Source 1), which was plotted and checked on a 1:24000 scale base map of the Connecticut shore. These point locations, observations, and the nearshore bathymetry were then used to delineate areas representing both observed eelgrass beds (Source 2) and potential eelgrass beds. Eelgrass beds were initially digitized at 1:24,000 scale, but have been edited and revised on screen at higher resolution.
Source 1 - Eelgrass Sample Points Coverage
1997
Source 2 - Observed Eelgrass Beds Coverage
University of Connecticut, Long Island Sound Resource Center
Mary DiGiacomo-Cohen
mailing and physical address
860-405-9015
Datum conversion - Using ESRI ArcInfo software, the Observed Eelgrass Beds layer was converted from the Connecticut State Plane Coordinate System of 1927 (NAD27) to the Connecticut State Plane Coordinate System of 1983 (NAD83). The NADCON (North American Datum CONversion) data transformation was used.
Source 2 - Observed Eelgrass Beds Coverage
1997
Source 2 - Observed Eelgrass Beds Coverage
State of Connecticut, Department of Environmental Protection
Using ArcView software, the Observed Eelgrass Beds Coverage was converted to Shapefile format.
Source 2 - Observed Eelgrass Beds Coverage
1997
Source 3 - Observed Eelgrass Beds Shapefile
State of Connecticut, Department of Environmental Protection
State of Connecticut, United States of America
Vector
G-polygon
101
Point
216
Lambert Conformal ConicLambert Conformal Conic41.20000041.866667-72.75000040.833333999999.999996499999.999998
coordinate pair
0.000250
0.000250
survey feet
North American Datum of 1983
Geodetic Reference System 80
6378137.000000
298.257222
1.000000
Explicit elevation coordinate included with horizontal coordinates
Observed Eelgrass Beds
Observed Eelgrass Areas stored as digital vector data
State of Connecticut, Department of Environmental Protection
OBJECTID
Internal feature number.
ESRI
Sequential unique whole numbers that are automatically generated.
Shape
Feature geometry.
ESRI
Coordinates defining the features.
AV_LEGEND
ArcView Legend field (decodes TYPE attribute). Density of the eelgrass bed.
State of Connecticut, Department of Environmental Protection
Low
Low density of eelgrass bed.
Medium
Medium density of eelgrass bed.
High
High density of eelgrass bed
Absent
Eelgrass is absent in bed
ACREAGE
Area of feature in acres (SHAPE_AREA divided by 43560).
State of Connecticut, Department of Environmental Protection
Number generated by dividing Shape_Area by 43,560.
TYPE
Describes density of the eelgrass bed.
State of Connecticut, Department of Environmental Protection
L
Low density of eelgrass bed.
M
Medium density of eelgrass bed
H
High density of eelgrass bed
A
Absent. Eelgrass is absent.
Coordinates defining the features.
SHAPE
Feature geometry.
ESRI
Coordinates defining the features.
FREQUENCY
Number of point locations (Eelgrass Sample Points) within the polygon.
State of Connecticut, Department of Environmental Protection
Whole numbers from 0 to 69.
SHAPE.area
SHAPE.len
Includes Observed Eelgrass Bed polygon features such as eelgrass density (AV_LEGEND), code for eelgrass density (TYPE), point frequency within each polygon (FREQUENCY), size of the feature in acres (ACREAGE), size of the feature in square feet (SHAPE_AREA), and perimeter of feature area (SHAPE_LENGTH). Use the AV_LEGEND attribute to symbolize features by density on a map. The AV_LEGEND attribute decodes the TYPE attribute.
State of Connecticut, Department of Enviromental Protection
mailing and physical address
79 Elm Street
Hartford
Connecticut
06106-5127
USA
860-424-3034
860-424-4054
dep.gisdata@ct.gov
Monday to Friday, 08:30 to 16:30 Eastern Standard Time
Observed Eelgrass Beds
Shapefile, Feature Class
ArcGIS
Zip file
http://www.ct.gov/deep
An online copy of the data may be accessed without charge.
The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving the data.
Geographic information sytem (GIS), computer-aided drawing or other mapping software is necessary to display, view and access the information.
20120119
State of Connecticut, Department of Environmental Protection
Jacqueline Mickiewicz, Mary DiGiacomo-Cohen
mailing and physical address
79 Elm Street
Hartford
Connecticut
06106-5127
USA
860-424-3540
860-424-4058
dep.gisdata@ct.gov
Monday to Friday, 08:30 to 16:30 Eastern Standard Time
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
http://www.esri.com/metadata/esriprof80.html
ESRI Metadata Profile