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Connecticut Towns for Clipping

Frequently-asked questions:


What does this data set describe?

Title:
Connecticut Towns for Clipping

Abstract:
Connecticut Towns for Clipping is a 1:24,000-scale polygon feature-based layer that should only be used to clip other 1:24,000-scale feature-based layers by town. The layer includes one polygon feature for each Connecticut town (municipality). For inland towns, town polygon features are entirely based on political boundary information depicted on the U.S. Geological Survey 7.5 minute topographic quadrangle maps. For towns along the Connecticut coastline, town polygon features are based on a combination of political boundary information published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps and a two-mile buffer along the Connecticut coastline that artificially expands the geographic area for coastal towns into the waters of Long Island Sound. The shoreline has been generalized and extended seaward by a distance of two miles to ensure features near the true shoreline (as depicted on the USGS topographic quadrangel maps) are included with the (clipped) output dataset results. The layer is based on information from USGS topographic quadrangle maps published between 1969 and 1984. There is one polygon feature in this layer for each Connecticut town with attribute information that denotes the Town number and Town name. This layer was originally published in 1994. With the exception of the Middletown-Portand town boundary, the 2005 edition includes the same features originally published in 1994. The Middletown-Portand town boundary was corrected and changed from its location, as depicted on the USGS topographic quadrangle maps, from along the banks of the Connecticut River in Portand to the middle of the Connecticut River south of Wilcox Island to the Pecausett Meadows area in Portland.

Supplemental information:
The Towns for Clipping layer was originally created in 1994 from an early version of the Town Master from USGS layer, also published by the State of Connecticut, Department of Environmental Protection. For additional information related to the original source of data from the U.S. Geological Survey, refer to the Data User Guides and Standards for 1:24,000-Scale Digital Line Graphs and Quadrangle Maps available from the U.S. Geological Survey, National Mapping Program.

  1. How should this data set be cited?

    State of Connecticut, Department of Environmental Protection (data compiler, editor and publisher), U.S. Geological Survey, National Mapping Program (data compiler), 19940101, Connecticut Towns for Clipping: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Other citation details:
    The USGS is the collector of the data (compiler). The State of Connecticut, Department of Environmental Protection is the creator and maintainer of the data layer (editor) and producer (publisher) of this information for use. The 2005 Edition includes the same set of geographic features published in 1994. However, the 2005 Edition differs from information published in 1994 primarily as a result of minor corrections and improvements to feature geometry. This layer includes information that is relatively static and does not change over time. Data is not updated. Data compiled at 1:24,000 scale.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -73.742172
    East: -71.781365
    North: 42.052612
    South: 40.963546

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/townclip.gif (GIF)
    Full view of Connecticut Towns for Clipping

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

    Beginning date: 1969
    Ending date: 1984
    Currentness reference:
    Publication dates of the USGS 7.5 minute topographic quadrangle maps for the State of Connecticut through 1984.

  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?

      Indirect spatial reference:
      Connecticut town names and numbers

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (169)

    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 Towns for Clipping
    Includes one polygon feature for each Connecticut town (municipality). For inland towns, town polygon features are based on political boundary information published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps. For towns along the Connecticut coastline, town polygon features are based on the political boundary information published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps that is combined with a two-mile buffer along the Connecticut coastline, artificially expanding the geographic area for coastal towns into the waters of Long Island Sound. (Source: State of Connecticut, Department of Environmental Protection and U.S. Geological Survey, National Mapping Program)

    OBJECTID
    Internal feature number. (Source: ESRI)
                      

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    TOWN_NO
    Town Number - ID number for the Connecticut Town (municipality), based on the Town Codes issued by the State of Connecticut, Office of the State Controller, which range from 1 to 169. (Source: State of Connecticut, Department of Environmental Protection)
                      

    Numeric value ranging from 1 to 169.

    TOWN
    Town Name - Text values that correspond to numeric TOWN_NO attribute values. TOWN is the English language equivalent of (decodes) the TOWN_NO field. (Source: State of Connecticut, Department of Environmental Protection)
                      

    Text value (town name).

    SHAPE.area
    SHAPE.len
    Entity and attribute overview:
    Includes one polygon feature for each Connecticut town (municipality). For inland towns, town polygon features are based on political boundary information published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps. For towns along the Connecticut coastline, town polygon features are based on the political boundary information published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps that is combined with a two-mile buffer along the Connecticut coastline, artificially expanding the geographic area for coastal towns into the waters of Long Island Sound. When this layer is used to clip features in other layers, features in the Connecticut portion of Long Island Sound that are within two miles of the Connecticut shoreline are included with the (clipped) output dataset results. Label polygon feature with the TOWN attribute to display town names.

    Entity and attribute detail citation:
    Connecticut Town numbers, based on the Town Codes issued by the State of Connecticut, range from 1 to 169 in the following order:
    
    Andover (1), Ansonia (2), Ashford (3), Avon (4), Barkhamsted (5), Beacon Falls (6), Berlin (7), Bethany (8), Bethel (9), Bethlehem (10), Bloomfield (11), Bolton (12), Bozrah (13), Branford (14), Bridgeport (15), Bridgewater (16), Bristol (17), Brookfield (18), Brooklyn (19), Burlington (20), Canaan (21), Canterbury (22), Canton (23), Chaplin (24), Cheshire (25), Chester (26), Clinton (27), Colchester (28), Colebrook (29), Columbia (30), Cornwall (31), Coventry (32), Cromwell (33), Danbury (34), Darien (35), Deep River (36), Derby (37), Durham (38), Eastford (39), East Granby (40), East Haddam (41), East Hampton (42), East Hartford (43), East Haven (44), East Lyme (45), Easton (46), East Windsor (47), Ellington (48), Enfield (49), Essex (50), Fairfield (51), Farmington (52), Franklin (53), Glastonbury (54), Goshen (55), Granby (56), Greenwich (57), Griswold (58), Groton (59), Guilford (60), Haddam (61), Hamden (62), Hampton (63), Hartford (64), Hartland (65), Harwinton (66), Hebron (67), Kent (68), Killingly (69), Killingworth (70), Lebanon (71), Ledyard (72), Lisbon (73), Litchfield (74), Lyme (75), Madison (76), Manchester (77), Mansfield (78), Marlborough (79), Meriden (80), Middlebury (81), Middlefield (82), Middletown (83), Milford (84), Monroe (85), Montville (86), Morris (87), Naugatuck (88), New Britain (89), New Canaan (90), New Fairfield (91), New Hartford (92), New Haven (93), Newington (94), New London (95), New Milford (96), Newtown (97), Norfolk (98), North Branford (99), North Canaan (100), North Haven (101), North Stonington (102), Norwalk (103), Norwich (104), Old Lyme (105), Old Saybrook (106), Orange (107), Oxford (108), Plainfield (109), Plainville (110), Plymouth (111), Pomfret (112), Portland (113), Preston (114), Prospect (115), Putnam (116), Redding (117), Ridgefield (118), Rocky Hill (119), Roxbury (120), Salem (121), Salisbury (122), Scotland (123), Seymour (124), Sharon (125), Shelton (126), Sherman (127), Simsbury (128), Somers (129), Southbury (130), Southington (131), South Windsor (132), Sprague (133), Stafford (134), Stamford (135), Sterling (136), Stonington (137), Stratford (138), Suffield (139), Thomaston (140), Thompson (141), Tolland (142), Torrington (143), Trumbull (144), Union (145), Vernon (146), Voluntown (147), Wallingford (148), Warren (149), Washington (150), Waterbury (151), Waterford (152), Watertown (153), Westbrook (154), West Hartford (155), West Haven (156), Weston (157), Westport (158), Wethersfield (159), Willington (160), Wilton (161), Winchester (162), Windham (163), Windsor (164), Windsor Locks (165), Wolcott (166), Woodbridge (167), Woodbury (168), and Woodstock (169).
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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?

    Howie Sternberg
    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
    Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time
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Why was the data set created?

Connecticut Towns for Clipping is a 1:24,000-scale layer that is only intended to be used for clipping other 1:24,000-scale spatial datasets by town. For example, use this layer to clip other layers such as Hydrography or Drainage Basins and create datasets of information for individual towns. Note, when this layer is used to clip features in other layers, features in the Connecticut portion of Long Island Sound that are within two miles of the Connecticut shoreline are included with the (clipped) output dataset results. Do not print the Towns for Clipping polygon features on a map. These polygon features were specifically designed for clipping other datasets and are not intended for displaying or printing town boundaries on a map. In particular, the polygon features for towns along the Connecticut coastline have been artificially enlarged to extend into Long Island Sound by a distance of two miles. The artificial nature of the southern portion of this layer ensures that features near the actual shoreline are included with the (clipped) output dataset. Use the layer named Town, which is also published by the State of Connecticut Department of Environmental Protection, to depict 1:24,000-scale Connecticut town boundaries on a map.

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How was the data set created?

  1. Where did the data come from?

    Source 1 - Town Master from USGS (source 1 of 4)

    State of Connecticut, Department of Environmental Protection (data compiler, editor and publisher), U.S. Geological Survey, National Mapping Program (data compiler), 19940101, Town Master from USGS layer: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Town Master from USGS is a 1:24,000-scale, polygon and line feature-based layer that includes all political boundary features depicted on all of the U.S. Geological Survey (USGS) 7.5 minute topographic quadrangle maps that cover the State of Connecticut. Line features include State, county, town (municipal), and borough boundaries. Polygon features depict the geographic areas for individual towns (municipalities) and cities and boroughs within individual towns. This layer is the primary data source for a set of political boundary layers published by the State of Connecticut, Department of Environmental Protection. The Town Master, Town, Towns for Clipping, Connecticut, and Connecticut Mainland layers are all ultimately derived from the polygon and line features of the Town Master from USGS layer. Note, the town boundary between Middletown and Portand was corrected and changed from its location, as depicted on the USGS topographic quadrangle maps, from along the banks of the Connecticut River in Portand to the middle of the Connecticut River south of Wilcox Island to the Pecausett Meadows area in Portland. Additionally, coastline and island feature information from the Hydrography Master layer was incorporated into the Town Master from USGS layer in order to enclose the land areas encompassed by towns adjacent to Long Island Sound and to define the islands that are part of these coastal towns. Features derived from the Hydrography Master layer are attributed with specific COASTA_COD and COASTP_COD values. Town Master from USGS is in ArcInfo Coverage format.

    Source 2 - Towns for Clipping (source 2 of 4)

    State of Connecticut, Department of Environmental Protection (data compiler, editor and publisher), U.S. Geological Survey, National Mapping Program (data compiler), 19940101, Connecticut Towns for Clipping coverage: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Towns for Clipping is in ArcInfo Coverage format. Originally published in 1994, the 2005 edition includes a corrected town boundary between Middletown and Portand and complete metadata.

    Source 3 - Town_Clip.shp (source 3 of 4)

    State of Connecticut, Department of Environmental Protection (data compiler, editor and publisher), U.S. Geological Survey, National Mapping Program (data compiler), 19940101, Connecticut Towns for Clipping shapefile: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Town_Clip.shp is in Shapefile format

    Source 4 - Town_Clip (source 4 of 4)

    State of Connecticut, Department of Environmental Protection (data compiler, editor and publisher), U.S. Geological Survey, National Mapping Program (data compiler), 19940101, Connecticut Towns for Clipping: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Town_Clip is in GeoDatabase Feature Class format

  2. What changes have been made?

    Date: 2005 (change 1 of 3)
    Create Towns for Clipping layer - All Connecticut town polygon features from the layer named 'Town Master from USGS' encoded as inland polygon features in Connectcut (STATE_COD = 'CT' and COASTP_COD = 1) were extracted and output to a separate ArcInfo Coverage named TOWNCLIP. All line features from the layer named 'Town Master from USGS' encoded as Coastline Arcs in Connecticut (STATE_COD = 'CT' and COASTA_COD = 2) were extracted and output to a second ArcInfo Coverage. These line features formed a continuous shoreline feature that ran from Greenwich to Stonington, Connecticut. This shoreline feature was then buffered a distance of two miles, which was output to a third ArcInfo Coverage. The seaward side of the two-mile buffer, located entirely in Long Island Sound, was manually copied into the TOWNCLIP coverage and used to outline the southern boundary for some of the coastal towns in situations where the actual state boundary between Connecticut and New York in Long Island Sound was farther than 2 miles from the Connecticut Coastline. Otherwise, the state boundary between Connecticut and New York formed the southern boundary such with Stonington, Connecticut. Consequently, town polygon features along the coastline were manually edited and enclosed with either the two-mile buffer or state boundary. Town number and Town name attribute values were visually inspected. All other polygon attributes originating from the source layer, Town Master from USGS, were removed. Finally, the smaller borough and city polygon features from the original Town Master from USGS layer were merged (and contiguous polygon features that were part of the same town were dissolved) to establish a single, all encompassing polygon feature for each town. The name of the resulting ArcInfo coverage was TOWNCLIP.

    Person responsible for change:
    Howie Sternberg
    State of Connecticut, Department of Environmental Protection
    Hartford
    Hartford, Connecticut 06106
    USA

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 1 - Town Master from USGS

    Data sources produced in this process:
    • Source 2 - Towns for Clipping

    Date: 2005 (change 2 of 3)
    Export to Shapefile format - Using ArcGIS 8.3, converted polygon feature data from an ArcInfo coverage named TOWNCLIP to a Shapefile named Town_Clip.shp. Excluded the AREA, PERIMETER, TOWNCLIP#, and TOWNCLIP-ID attributes from the Shapefile because their values are only maintained by ArcInfo software with spatial data that is ArcInfo coverage format. Using ArcView 3.3 software and an Avenue script named Table.ExportSorted (Peter Girard, author) available from the ArcScripts download page at www.esri.com, permanently sorted the shapefile's polygon feature attribute table in ascending order by Town number.

    Person responsible for change:
    Howie Sternberg
    State of Connecticut, Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106
    USA

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 2 - Towns for Clipping

    Data sources produced in this process:
    • Source 3 - Town_Clip.shp

    Date: 2006 (change 3 of 3)
    Convert to GeoDatabase Feature Class format - Defined new Feature Class named Town_Clip; and imported the attribute definitions, loaded features and imported metadata from Town_Clip.shp shapefile. 
    
    Spatial Reference Properties for Feature Class:
    
    Coordinate System: NAD_1983_StatePlane_Connecticut_FIPS_0600_Feet
    XY Domain MinX: 100000; MaxX: 2247483.645
    XY Domain MinY: 200000; MaxY: 2347483.645
    Precision: 1000

    Person responsible for change:
    Howie Sternberg
    State of Connecticut, Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106
    USA

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 3 - Town_Clip.shp

    Data sources produced in this process:
    • Source 4 - Town_Clip

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

  1. How well have the observations been checked?

    This data is partially derived from political boundary (linear) feature types identified by the USGS that are used to outline town polygon features. All attributes have valid values. Values are within defined domains. The TOWN_NO (Town number) polygon attribute was manually entered and visually inspected and compared to information on the USGS 7.5 minute topographic quadrangle maps. The TOWN (Town name) attribute is the English equivalent of (decodes) the TOWN_NO polygon attribute and was populated though a table join to a town lookup table. There are no line features or attributes.

  2. How accurate are the geographic locations?

    All town polygon outlines that not generated from the two-mile buffer of the Connecticut coastline comply with United States National Map Accuracy Standards for 1:24,000 scale maps. According to this standard, not more than 10 percent of the points tested are to be in error by more than 1/50 inch (40 feet) measured on the publication scale of a USGS 7.5 minute topographic quadrangle map.

  3. How accurate are the heights or depths?

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

    The completeness of the data partially reflects the USGS National Mapping Division standards for feature content of the data sources, which are the Large Scale (7.5 minute) Digital Line Graph (DLG) files available from the USGS. For Connecticut, the Large Scale DLG files used to create this layer are for the 1:24,000-scale topographic quadrangle maps published between 1969 and 1984.  The data is complete in the sense that it accurately reflects the contents of the most recently published USGS topographic quadrangle maps available at the time the State of Connecticut, Department of Environmental Protection began creating the layer. More recent quadrangle maps have been published by the USGS since 1984; however, the State of Connecticut did not incorporate this information into the layer. This data is not updated.

  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. There are no line features. 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 4 feet (fuzzy tolerance) and a minimum allowed overshoot length of 10 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. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet). 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 and the U.S. Geological Survey, National Mapping Program as the source for this information. For example, include the following data source description when printing this layer on a map: Towns - From the Towns for Clipping layer, compiled and published by CT DEP and USGS. Source map scale is 1:24,000.

Distributor 1 of 1

  1. Who distributes the data set?

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

    860-424-3540 (voice)
    860-424-4058 (FAX)
    dep.gisdata@ct.gov
    Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time

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

    Connecticut Towns for Clipping

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?

    • Availability in digital form:


    • Data format:
      in format Shapefile, Feature Class, ArcInfo Coverage (version ArcGIS)
      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: 20111209

Metadata author:
Howie Sternberg
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
Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time

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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