Connecticut Mainland Line includes the line features of a layer named Connecticut Mainland. Connecticut Mainland is a 1:24,000-scale, polygon and line feature-based layer that depicts the geographic area encompassed by and the boundary for the State of Connecticut with an additional linear shoreline feature separating the Connecticut mainland from the waters of Long Island Sound. The layer includes a polygon feature representing the Connecticut mainland, a polygon feature representing Connecticut waters in Long Island Sound and approximately 700 polygon features representing Connecticut islands in Long Island Sound. The layer is based on information from USGS topographic quadrangle maps published between 1969 and 1984 and latitude and longitude coordinates that define the boundary between the states of Connecticut and New York in Long Island Sound. Feature length and geographic area are encoded for linear and polygon features, respectively. This layer was originally published in 2005.
In 2004, the State of Connecticut, Department of Environmental Protection developed automated procedures to maintaining feature topology and attribute integrity for the Town Master from USGS layer and layers derived from the Town Master from USGS layer such as Connecticut Mainland. Using ArcInfo Workstation 8.3 software and Arc Macro Language (AML) scripting environment, the automated procedures were recorded in an AML file named MAKECOVER.AML for the political boundary category of data published by the State of Connecticut, Department of Environmental Protection. The MAKECOVER.AML maintains the features and feature attribute data for the Town Master from USGS, Town Master, Town, Connecticut, and Connecticut Mainland layers. Unlike the other derived layers, the Connecticut Mainland layer was first derived in 2005. 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.
Publication dates of the USGS 7.5 minute topographic quadrangle maps for the State of Connecticut through 1984.
Includes line features representing the Connecticut state boundary, the Connecticut coastline, and the shorelines for Connecticut islands in Long Island Sound. (Source: State of Connecticut, Department of Environmental Protection and U.S. Geological Survey, National Mapping Program)
Internal feature number. (Source: ESRI)
Feature geometry. (Source: ESRI)
Town Boundary Arc Code - Numeric values that identify town boundary line feature types. (Source: State of Connecticut, Department of Environmental Protection and U.S. Geological Survey, National Mapping Program )
| Value | Definition |
|---|---|
| 101 | Connecticut State Boundary |
| 102 | Connecticut Coastline |
| 103 | Connecticut Island Coastline |
Town Boundary Type - Text values that correspond to numeric TBARC_COD attribute values. TOWN_ARC is the English language equivalent of (decodes) the TBARC_COD field. (Source: State of Connecticut, Department of Environmental Protection and U.S. Geological Survey, National Mapping Program)
ArcView Legend. A text field for symbolizing different feature types on a map. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| Coastline | Includes features with TBARC_COD attribute values 102, and 103. |
| State Boundary | Includes features with TBARC_COD attribute value 101. |
Internet Mapping Software Legend. A text field for classifying and symbolizing feature types in a simple manner for an Internet map. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| Coastline | Includes features with TBARC_COD attribute values 102 and 103. |
| State Boundary | Includes features with TBARC_COD attribute value 101. |
Coastal Arc Code - Identifies line features that are landward and seaward of a series of connecting hydrography line features that define a shoreline along the coast. These connecting hydrography line features that define the shoreline along the coast are referred to as Coastline Arcs and have a COASTA_COD value of 2. Coastline Arc features from the Hydrography layer have been incorporated into the Town Master layer to enclose town polygon features along the coast. Coastline Arcs define a cartographic boundary that separates inland (landward) features from coastal (seaward) features. This shoreline boundary does not represent a line of demarcation between tidal and non-tidal waters or between fresh, saline and brackish waters. Rather, these features define a standard shoreline boundary that is often incorporated into other layers compiled at 1:24,000 scale for consistency. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| 1 | Inland Arcs - Line features that are inland (landward) of the line of Coastline Arcs, which have COASTA_COD values of 2. |
| 2 | Coastline Arcs - Line features that define a coastline that separates inland from coastal features. This is a cartographic boundary that often defines the shoreline in other 1:24,000-scale datalayers published by the State of Connecticut, Department of Environmental Protection. Note, this boundary line does not represent a line of demarcation between tidal and non-tidal waters or between fresh, saline and brackish waters. |
| 3 | Island Interior Arcs - Line features that separate (define a portion of the boundary of) smaller polygon features within Coastal Island polygons. For example, a State or Town boundary line that cuts through an island. |
| 4 | Island Coastline Arcs - Line features that define the shorelines for Coastal Island Polygon features. Coastal Island Polygon features have a COASTP_COD value of 2. |
| 5 | Open Water Arcs - Line features seaward of the line of Coastline Arcs that outline Coastal Water Polygon features. Coastal Water Polygon features are polygon features with a COASTP_COD value of 3. In this layer, Open Water Arcs mostly define unofficial town boundaries in Long Island Sound for towns along the Connecticut coastline. These boundaries are partially based on town boundary information published on the USGS topographic quadrangle maps and extend from the Connecticut coastline to the Connecticut - New York state boundary in Long Island Sound. |
Coastal Arc - Text values that correspond to numeric COASTA_COD attribute values. COAST_ARC is the English language equivalent of (decodes) the COASTA_COD field. (Source: State of Connecticut, Department of Environmental Protection)
Calculated length of feature in miles. Note, LENGTH_MI 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)
The Connecticut Mainland layer includes polygonal and linear features for the state of Connecticut boundary, the Connecticut shoreline and island features in Long Island Sound, as published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps. Information encoded about features includes standard symbology classification schemes, feature area in acres and square miles, and feature length in miles. Use the AV_LEGEND attribute to symbolize polygon and line features by type on a map. Use the IMS_LEGEND attribute to more generally symbololize line features on a map.
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.
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Connecticut Mainland is 1:24,000-scale base map data. For base map purposes, use this layer with other 1:24,000-scale base map data such as Town, Hydrography, Waterbody, Named Waterbody, Roads and Trails, Railroads, and Airports. All of these layers include information for Connecticut. Use Connecticut Mainland as a backgound layer to cartographically distinguish areas of water from land. Connecticut Mainland may be used as a possible data source for other 1:24,000-scale layers having features that should coincide with the Connecticut State boundary shown on USGS topographic quadrangle maps. Not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)
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, 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.
Connecticut Mainland is in ArcInfo Coverage format.
A line feature-based layer that depicts the boundary for the State of Connecticut with additional linear shoreline features separating the Connecticut mainland from the waters of Long Island Sound and delineating the shorelines of Connecticut islands in Long Island Sound. This layer only includes information for Connecticut. ConnecticutMainland_Line.shp is in Shapefile format.
A line feature-based layer that depicts the boundary for the State of Connecticut with additional linear shoreline features separating the Connecticut mainland from the waters of Long Island Sound and delineating the shorelines of Connecticut islands in Long Island Sound. This layer only includes information for Connecticut. Connecticut_Mainland_Line is in GeoDatabase Feature Class format.
Create Connecticut Mainland - The State of Connecticut, Department of Environmental Protection developed an automated procedure to maintain feature topology and attribute integrity for the Connecticut Mainland layer by creating (deriving) the layer from a layer named Town Master from USGS. This procedure is documented in an Arc Macro Language (AML) script named MAKECOVER.AML for the political boundary category of data for the State of Connecticut, Department of Environmental Protection. This procedure combined the geometry of certain features and ensured consistent attribute values by programmatically joining lookup data tables to decode numeric code fields. The MAKECOVER.AML creates the Connecticut Mainland layer by extracting and processing features from the Town Master from USGS layer. All polygon and line features from the Town Master from USGS layer that defined boundaries in Connecticut were extracted and output to a separate ArcInfo Coverage named CONNMAINLAND. Subsequently, the IMS_LEGEND, STATE_COD, FIPS_COD, TOWN_NO, TOWN, CNTY_COD, COUNTY, CONN_CITY, CONN_BORO polygon attributes and STATE_COD, STATE_FLG, FIPS_FLG, CONN_FLG, TOWN_FLG, CITY_FLG, BORO_FLG, TNO_LEFT, TOWN_LEFT, TNO_RIGHT, TOWN_RIGHT, CITY_LEFT, CITY_RIGHT and BOROUGH line attributes were removed and polygon features were dissolved, merging all adjacent town area polygon features into a single polygon feature representing the Connecticut mainland. The MAKECOVER.AML was executed in 2005 in order to derive the Connecticut Mainland layer from the 2005 Edition of the Town Master from USGS layer. The name of the resulting ArcInfo coverage created by this automated process is CONNMAINLAND. Note, all information is based on boundary lines depicted on USGS topographic quadrangle maps with the exception of most of the state boundary in Long Island Sound. The boundary line between the states of Connecticut and New York is described in Special Laws of Connecticut, Volume 16, pages 1104-1108, Senate Bill #322, An Act Establishing The Boundary Line Between Connecticut and New York. This Special Act documents the latitude and longitude coordinates of the state boundary monuments on the ground and points in the waters of Long Island Sound. These geodetic positions are based on Clark's spheroid of 1866 and are in degrees, minutes and seconds (DMS). The following boundary points enumerated in this act were used to define the state boundary in Long Island Sound. Point No. 170: Latitude 40 57 03.228, Longitude -73 36 46.418 Point No. 171: Latitude 41 15 31.321, Longitude -72 05 24.685 Point No. 172: Latitude 41 17 26.341, Longitude -72 01 10.937 Point No. 173: Latitude 41 18 37.835, Longitude -71 55 47.626 Point No. 174: Latitude 41 18 16.249, Longitude -71 54 28.477
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Export to Shapefile format - Converted line feature data from an ArcInfo coverage named CONNMAINLAND to a Shapefile named ConnecticutMainland_Line.shp. Excluded the FNODE#, TNODE#, LPOLY#, RPOLY#, LENGTH, CONNMAINLAND#, and CONNMAINLAND-ID attributes from the Shapefile because their values are only maintained by ArcInfo software with data that is in ArcInfo Coverage format.
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Convert to GeoDatabase Feature Class format - Defined new Feature Class named Connecticut_Mainland_Line; and imported the attribute definitions, loaded features and imported metadata from ConnecticutMainland_Line.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
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This data retains the political boundary (linear) feature types identified by the USGS and adds new polygon feature types of importance to the State of Connecticut for the purpose of mapping areas of the State of Connecticut on land and in the waters of Long Island Sound. All attributes have valid values. Values are within defined domains. The accuracy test for the TBARC_COD and TBPOLY_COD attribute values was conducted by comparing the political boundaries published on the source topographic quadrangle maps with 1:24,000-scale check plots or interactive displays of the data on a computer graphic system. These checkplots and computer displays depicted the features in different colors based on their respective TBARC_COD and TBPOLY_COD values for comparison with the paper quadrangle maps. The TOWN_ARC, TOWN_POLY, AV_LEGEND, and IMS_LEGEND attribute values are based on TBARC_COD and TBPOLY_COD values. TOWN_POLY is the English language equivalent of (decodes) the TBPOLY_COD field for polygon features. TOWN_ARC is the English language equivalent of (decodes) the TBARC_COD field for line features. AV_LEGEND is a broad classification of TBPOLY_COD and TBARC_COD values for polygon and line features, respectively. Based on the TBPOLY_COD and TBARC_COD attribute values, the TOWN_POLY, TOWN_ARC, and AV_LEGEND fields were populated through table joins to lookup tables. These decode values were not manually entered. The COASTA_COD line attributes for the shoreline features were transferred with the Coastal Arc (coastline) features copied from the Hydrography Master layer. All other polygon and line features were manually selected and assigned COASTP_COD and COASTA_COD values based on their relative landward and seaward orientation to Coastline Arcs. The COAST_POLY and COAST_ARC attributes decode the COASTP_COD and COASTA_COD attribute values and were populated through table joins to lookup tables. The COAST_POLY field decodes the COASTP_COD field for polygon features. The COAST_ARC field decodes the COASTA_COD field line features. The ACREAGE (area in acres) and AREA_SQMI (area in square miles) fields were automatically calculated for each polygon feature based on computer generated feature area in square feet. The LENGTH_MI (length in miles) field was automatically calculated for each line feature base on computer generated feature length.
This data complies 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.
The completeness of the data 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.
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 4 feet (fuzzy tolerance) and a minimum allowed overshoot length of 10 feet (dangle length).
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: Political Boundaries - From the Connecticut Mainland layer, compiled and published by CT DEP and USGS. Source map scale is 1:24,000.
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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.
| Data format: | in format Shapefile, Feature Class, ArcInfo Coverage (version ArcGIS) |
|---|---|
| Network links: | http://www.ct.gov/deep |
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.
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