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Connecticut Lake Bathymetry Polygon

Frequently-asked questions:


What does this data set describe?

Title:
Connecticut Lake Bathymetry Polygon

Abstract:
Lake Bathymetry is a polygon feature-based layer that includes bathymetric (water depth) information for selected reservoirs, lakes, ponds and coves in Connecticut. The layer is based on information collected by the State of Connecticut, Department of Environmental Protection over a period of time using a variety of different techniques and equipment including manual depth soundings, use of an electronic depth sounder, use of a GPS receiver to locate the boat, and digitizing previously published bathymetry maps. Attribute information is comprised of codes to depict water depth, waterbody indentification, collection method, and to cartographically symbolize features on a map. Data is compiled at a variety of scales and resolutions, depending on the collection method used for a particular waterbody. This data is not updated, however bathymetry information for addtional waterbodies may become available and included in this layer as new information is collected. The Bathymetry layer includes bathymetry for the following Connecticut lakes, ponds and coves: Alexander Lake, Amos Lake, Anderson Pond, Aspinook Pond, Avery Pond, Babcock Pond, Ball Pond, Bantam Lake, Bashan Lake, Batterson Park Pond, Beach Pond, Beachdale Pond, Beseck Lake, Bigelow Pond, Billings Lake, Black Pond, Bolton Lake Lower, Bolton Lake Middle, Bolton Lake Upper, Bolton Notch Pond, Breakneck Pond, Burr Pond, Candlewood Lake, Cedar Lake, Chamberlain Lake, Chapman Pond, Colebrook River Reservoir, Congamond Lakes, Coventry Lake, Cresent Pond, Crow Point Cove, Crystal Lake, Dodge Pond, Dog Pond, Dooley Pond, Eagleville Lake, East Twin Lake, Frash Pond, Gardner Lake, Glasgo Pond, Gorton Pond, Great Hollow Pond, Green Falls Reservoir, Halls Pond, Hamburg Cove, Hampton Reservoir, Hatch Pond, Higganum Reservoir, Highland Lake, Holbrook Pond, Hopeville Pond, Horse Pond, Howells Pond, Jurovaty Pond, Keach Pond, Keeney Cove, Killingly Pond, Lake Hayward, Lake Housatonic, Lake Kenosia, Lake Lillinonah, Lake Of Isles, Lake Saltonstall, Lake Wintergreen, Lake Zoar, Lantern Hill Pond, Leonard Pond, Little Pond, Long Pond, Maltby Lake #1, Maltby Lake #2, Maltby Lake #3, Mamanasco Lake, Mansfield Hollow Reservoir, Mashapaug Lake, McDonough Lake, Messerschmidt Pond, Millers Pond, Mohawk Pond, Mono Pond, Moodus Reservoir Lower, Moodus Reservoir Upper, Moosup Pond, Morey Pond, Mount Tom Pond, Mudge Pond, North Farms Reservoir, Norwich Pond, Pachaug Pond, Park Pond, Pataconk Reservoir, Pataganset Lake, Pickerel Lake, Pine Acres Lake, Powers Lake, Quaddick Reservoir Lower, Quaddick Reservoir Middle, Quaddick Reservoir Upper (Stump Pond), Quinebaug Lake, Quonnipaug Lake, Rainbow Reservoir, Red Cedar Lake, Rogers Lake, Roseland Lake, Salmon Cove, Saugatuck Reservoir, Shenipsit Lake, Silver Lake, South Spectacle Lake, Squantz Pond, Stillwater Pond, Tyler Lake, Uncas Lake, Waramaug Lake, West Branch Reservoir, West Hill Pond, West Side Pond, West Thompson Reservoir, West Twin Lake, Wethersfield Cove, Winchester Lake, Wonoscoponuc Lake, Wood Creek Pond, Wrights Cove, and Wyassup Lake. The 2011 Edition added the following lakes: Allen Brook Pond, Ashland Pond, Barber Pond, Butterworth Dam, Day Pond, Gay City Pond, Lost Pond, Schreeder Pond, Twin Lakes North, Twin Lakes South, Williams Pond.

  1. How should this data set be cited?

    State of Connecticut, Department of Environmental Protection (data compiler, editor, and publisher), 2003, Connecticut Lake Bathymetry Polygon: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut USA.

    Online links:
    Other citation details:
    The State of Connecticut, Department of Environmental Protection is the collector of the data (compiler), the creator and maintainer of the data layer (editor), and producer (publisher) of this information for use.

    This is part of the following larger work:

    Robert P. Jacobs, Eileen B. O'Donnell, William B. Gerrish, 2002, A Fisheries Guide to Lakes and Ponds of Connecticut: Connecticut Department of Environmental Protection BulletinDEP Bulletin 35, Connecticut Department of Environmental Protection, Hartford, Connecticut.

    Online links:
    Other citation details:
    ISBN 0-942085-11-6

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -73.542601
    East: -71.777815
    North: 42.062240
    South: 41.165460

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/lakebathymetrypolylinefullview.gif (GIF)
    Full view of lake bathymetry polygon and line features

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/lakebathymetrypolylinedetailview.gif (GIF)
    Detailed view of lake bathymetry polygon and line features.

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/lakebathymetrypolydetailview.gif (GIF)
    Detail view of lake bathymetry polygon features

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

    Beginning date: 1959
    Ending date: 2002
    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 (1901)

    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 0.000250.
      Ordinates (y-coordinates) are specified to the nearest 0.000250.
      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?

    Connecticut Lake Bathymetry Polygon
    Lake Bathymetry represented as polygon features  (Source: of Connecticut, Department of Environmental Protection )

    OBJECTID
    Internal feature number. (Source: ESRI)
                      

    Sequential unique whole numbers that are automatically generated.

    BATHYP_COD
    Bathymetry Polygon Code - Numeric values that identify bathymetry polygon feature types.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    ValueDefinition
    1
    Water
    3
    Island
    4
    Marsh

    BATHY_POLY
    Bathymetry Polygon Type. Text values that correspond to numeric BATHYP_COD attribute values. BATHY_POLY is the English language equivalent of (decodes) the BATHYP_COD field.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Text Value

    AV_LEGEND
    ArcView Legend. A text field for symbolizing different feature types on a map.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Text Value

    WB_NO
    Waterbody Number - ID number of waterbody (lake, cove, etc) in this layer for which there is bathymetry data.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Numeric Value

    WBNAME
    Waterbody Name - Name of the waterbody as listed in the publication entitled, A Fisheries Guide to the Lakes and Ponds of Connecticut. Some waterbodies my not be listed in this publication.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Text Value

    WBTOWN
    Waterbody Town - The names of one or more towns the waterbody is located in.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Text Value

    LAKE_NO
    Lake Number - ID number of named lake as identified in the Hydrography layer, also published by the State of Connecticut, Department of Environmental Protection.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Numeric Value

    BAY_NO
    Bay Number - ID number of named bay or cove as identified in the Hydrography layer, also published by the State of Connecticut, Department of Environmental Protection  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Numeric Value

    METHOD_COD
    Data Capture Method Code - A numeric code used to denote the general method used in the field to collect water depth information. Different methods were used, depending on techniques available at the time information was collected in the field.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    ValueDefinition
    1
    Manual soundings
    2
    Depth finder
    3
    GPS and depth finder

    METHOD
    Data Capture Method  (Source: State of Connecticut, Department of Environmental Protection )
                      

    See Enumerated Domain Value Definitions for METHOD_COD attribute.

    DATADATE
    Data Capture Date - Year bathymetry data was captured (collected) in the field  (Source: State of Connecticut, Department of Environmental Protection )
                      

    4 digit numeric value corresponding to a year

    DEPTH_FT
    Open Water Depth in Feet - Estimated depth of the water (polygon) based on the depth of the bounding water contour (line) features. The estimated DEPTH_FT value for a water polygon is half the difference between the shallowest and deepest contour. For example, a water polygon bound by a shoreline feature (zero depth) and depth contour of 4 feet is assigned a DEPTH_FT value of 2 feet.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Numeric Value

    ACREAGE
    Calculated area of polygon feature in acres. Note, ACREAGE values are not automatically updated after modifying feature geometry (shape). Values must be recalculated after features are edited, simplified, generalized, clipped, dissolved, etc.  (Source: State of Connecticut, Department of Environmental Protection )
                      

    Numeric Value

    SHAPE
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    SHAPE.area
    SHAPE.len
    Entity and attribute overview:
    Includes bathymetric information such as depth contours, shoreline delineations and depths of areas of open water between contours. Information encoded about these features includes depth, waterbody name, data collection method, and a standard cartographic symbology classification scheme for classifying features on a map. Use the WB_NO field to uniquely identify waterbodies. Use the AV_LEGEND attribute to symbolize features by type on a map. Use the DEPTH_FT line attribute to label depth contours on a map. Use the DEPTH_FT polygon attribute to gradationally shade (symbolize) areas of water according to depth on a map. 
    
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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?

    Bruce Hunter and Tom Nosal of the State of Connecticut, Department of Environmental Protection developed the techniques and procedures for collecting, processing and preparing bathymetry information collected in the field for use and interpretation. Over a period of time, they systematically created detailed datasets of water depth information using a variety of different techniques. For example, they prepared point data sets of water depth information designed for use with mapping software that generates depth contours. Bill Gerrish, also of the State of Connecticut Department of Environmental Protection processed and edited these detailed datasets of water depth information in order to generate water depth contours for individual lakes and assembled this information into a single, statewide layer.

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

    William Gerrish
    Connecticut Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106-5127
    USA

    860-424-3474 (voice)
    860-424-4070 (FAX)
    dep.gisdata@ct.gov
    Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Tiime
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Why was the data set created?

This dataset displays the bathymetry (water depth) of selected lakes in Connecticut.  Use this layer with hydrography or other waterbody datalayers to display water depth.

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How was the data set created?

  1. Where did the data come from?

  2. What changes have been made?

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

  1. How well have the observations been checked?

    The Lake Bathymetry layer retains the feature types and information identified by the State of Connecticut, Department of Environmental Protection. This information was obtained from the previously published bathymetry maps and data. All attributes have valid values. Values are within defined domains. The WB_NO and DEPTH_FT attribute values were assigned to line features through a combination of automated and manual processes. The accuracy test for the WB_NO and DEPTH_FT attributes was conducted by inspecting paper check plots or interactive displays of the data on a computer graphic system by symbolizing, labeling and selecting depth contours by WB_NO and DEPTH_FT values. The value for the DEPTH_FT attribute assigned with open water (polygon) features is based on the depth of the bounding water contour (line) features. The estimated DEPTH_FT value for a water polygon is half the difference between the shallowest and deepest contour. For example, a water polygon bound by a shoreline feature (zero depth) and depth contour of 4 feet is assigned a DEPTH_FT value of 2 feet. DEPTH_FT attribute values for polygon features were manually assigned. AV_LEGEND is a broad classifications of Lake Bathymetry line features . The WBNAME, WBTOWN, LAKE_NO, BAY_NO, METHOD_COD, and DATADATE were not manually entered. These additional fields were populated by joining both the line and polygon feature attribute tables to a lookup data table with WB_NO as the relate key field. This lookup table contained this information for each waterbody. The METHOD value was populated by joining to a lookup table with METHOD_COD as a relate key. The ACREAGE (area in acres) field was automatically calculated for each polygon feature based on computer generated feature area in square feet. 
    

  2. How accurate are the geographic locations?

    The horizontal positional accuracy of this data is unknown. 
    

  3. How accurate are the heights or depths?

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

    The completeness of the data reflects the availability of digital information at the time the layer was published. 

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

    Polygon features conform to the following topological rules. Polygons are single part. There are no duplicate polygons. Polygons do not self overlap. Polygons do not overlap other polygons. Polygons are bound by lines. Line features conform to the following topological rules. Lines are single part. There are no duplicate lines. Lines do not self overlap. Lines do not overlap other lines. Lines intersect only at nodes, and nodes anchor the ends of all lines. Lines do not overshoot or undershoot other lines they are supposed to meet and intersect. The tests of logical consistency were performed by the State of Connecticut using ESRI ArcInfo software to maintain feature topology in ArcInfo coverage format. The data is topologically clean. The ArcInfo Clean function was repeatedly used following edits to verify topology and enforce a minimum distance between vertices of 47.927 feet (fuzzy tolerance) and a minimum allowed overshoot length of 0 feet (dangle length). 
    

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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: None. The data is in the public domain and may be redistributed.
Use constraints:
No restrictions or legal prerequisites for using the data. Although this data set has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection 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 State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data 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. 

Distributor 1 of 1

  1. Who distributes the data set?

    State of Connecticut, Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106-5127
    USA

    860-424-3540 (voice)
    860-424-4058 (FAX)
    dep.gisdata@ct.gov

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

    Connecticut Lake Bathymetry Polygon

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?

    • Availability in digital form:


    • Data format:
      in format Shapefile (version ArcGIS 9.3.1) Size: 71.712
      Network links:http://www.ct.gov/deep

    • Cost to order the data: An online copy of the data may be accessed without charge.


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

    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. 
    

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

    Geographic information sytem (GIS), computer-aided drawing or other mapping software is necessary to display, view and access the information.

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Who wrote the metadata?

Dates:
Last modified: 20111208

Metadata author:
Bill Gerrish, Howie Sternberg
State of Connecticut, Department of Environmental Protection
79 Elm Street
Hartford, Connecticut 06106
USA

860-424-3540 (voice)
dep.gisdata@ct.gov

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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