Connecticut Town Master from USGS Line includes the line features of a layer named Town Master from USGS. 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). A town may be represented by more than one polygon feature. For example, in addition to representing the portion of a town on the mainland, a polygon feature may also define an island along the coast or a borough that is also part of a town. 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. Attribute information is comprised of codes to classify and cartographically symbolize political boundaries by type and identify the geographic areas encompassed by individual towns. Polygon feature attributes include state, county, and town codes and names. Feature length and geographic area are encoded for linear and polygon features, respectively. 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. Some attribute information has been slightly modified and made easier to use.
In 2004, the State of Connecticut, Department of Environmental Protection developed an automated procedure to maintain feature topology and attribute integrity for the Town Master from USGS and related layers. Using ArcInfo Workstation 8.3 software, this automated procedure was developed to systematically maintain a set of related political boundary data for the State of Connecticut, Department of Environmental Protection. These automated procedures were developed using the Arc Macro Language (AML) scripting environment and are recorded in an AML file named MAKECOVER.AML for the political boundary category of data for 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 Towns, Connecticut and Connecticut Mainland layers. 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 State, county, town and borough boundaries; the Long Island Sound coastline; the shorelines for islands in Long Island Sound; and closure lines that enclose out-of-state town polygons situated along the outer edges of the set of USGS topographic quadrangle maps that cover the State of Connecticut. (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 |
|---|---|
| 0 | Closure Line |
| 101 | Connecticut State Boundary |
| 102 | Connecticut Coastline |
| 103 | Connecticut Island Coastline |
| 104 | Connecticut Town Boundary |
| 105 | Connecticut City Boundary (that isn't also a Connecticut Town Boundary) |
| 106 | Connecticut Borough or Village Boundary (that isn't also a Connecticut Town Boundary) |
| 107 | Connecticut County Boundary |
| 201 | Out of State State Boundary |
| 202 | Out of State Coastline |
| 203 | Out of State Island Coastline |
| 207 | Out of State Town Boundary |
| 206 | Out of State Borough Boundary |
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 |
|---|---|
| Borough | Includes features with TBARC_COD attribute values 106 and 206. |
| City | Includes features with TBARC_COD attribute values 105 and 205. |
| Coastline | Includes features with TBARC_COD attribute values 102, 103, 202, and 203. |
| County Boundary | Includes features with TBARC_COD attribute values 107 and 207. |
| No Show | Includes features with TBARC_COD attribute value 0. |
| State Boundary | Includes features with TBARC_COD attribute values 101 and 201. |
| Town Boundary | Includes features with TBARC_COD attribute values 104 and 204. |
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, 103, 202 and 203. |
| No Show | Includes features with TBARC_COD attribute value 0, 105, 106, 205, and 206. |
| State Boundary | Includes features with TBARC_COD attribute values 101 and 201. |
| Town Boundary | Includes features with TBARC_COD attribute values 104, 107, 204, and 207. |
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)
Connecticut State Code - Identifies features located in Connecticut (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| CT | Connecticut feature |
State Boundary Flag - Identifies line features representing state boundaries for Connecticut, Massachussets, New York and Rhode Island (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| False | Not a State boundary |
| True | State boundary |
FIPS County Boundary Flag - Identifies line features representing county boundaries for Connecticut, Massachussets, New York and Rhode Island (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| False | Not a FIPS boundary |
| True | FIPS boundary |
Connecticut State Boundary Flag - Identifies line features representing the state boundariy for Connecticut. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| False | Not a Connecticut State boundary |
| True | Connecticut State boundary |
Connecticut Town Boundary Flag - Identifies line features that define Connecticut Town boundaries, including unofficial boundaries between Connecticut towns in Long Island Sound. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| False | Not a Connecticut Town boundary |
| True | Connecticut Town boundary |
Connecticut City Boundary Flag - Identifies line features for Connecticut cities. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| False | Not a Connecticut City feature |
| True | Connecticut City feature |
Connecticut Borough Boundary Flag - Identifies line features for Connecticut boroughs and villages with boundaries that appear on the USGS7.5 minute topographic quadrangle maps. May not include all Connecticut boroughs and villages. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| False | Not a Connecticut borough or village boundary feature |
| True | Connecticut borough or village boundary feature |
Connecticut County Boundary Flag - Identifies line features representing Connecticut County boundaries, including features that define the Connecticut coastline. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| False | Not a Connecticut County boundary |
| True | Connecticut County boundary |
Town Number Left - ID number for the Connecticut town (municipality) on the left side of feature. Values are based on the Town Codes issued by the State of Connecticut, Office of the State Controller. (Source: State of Connecticut, Department of Environmental Protection)
Town Left - Text values that correspond to numeric TNO_LEFT attribute values. TOWN_LEFT is the English language equivalent of (decodes) the TNO_LEFT field (Source: State of Connecticut, Department of Environmental Protection)
Town Number Right - ID number for the Connecticut town (municipality) on the right side of feature. Values are based on the Town Codes issued by the State of Connecticut, Office of the State Controller. (Source: State of Connecticut, Department of Environmental Protection)
Town Right - Text values that correspond to numeric TNO_RIGHT attribute values. TOWN_RIGHT is the English language equivalent of (decodes) the TNO_RIGHT field. (Source: State of Connecticut, Department of Environmental Protection)
City Name Left - Name of Connecticut city on the left side of feature. (Source: State of Connecticut, Department of Environmental Protection)
City Name Right - Name of Connecticut city on the right side of feature. (Source: State of Connecticut, Department of Environmental Protection)
Borough - Name of Connecticut borough of village on either the left or right side of line feature. (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)
Includes polygonal and linear features for political boundary information published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps. Polygon and line features primarily represent town areas and boundaries, respectively, with attributes that distinguish state, county, town (municipal) and borough areas and boundaries. Information encoded about features includes Town Boundary polygon and arc (line) type classification, standard symbology classification schemes, state, town, county codes, feature area feature area in acreage and square miles, and feature length in miles. Use the AV_LEGEND attribute to symbolize features by type. Use the IMS_LEGEND attribute to more generally symbolize the features by type. To define a layer that only includes features in Connecticut, query line and polygon features for STATE_COD equal to "CT". To define a layer that includes political boundary line features typically displayed on a map, exclude unnecessary features by querying line features for AV_LEGEND not equal to "No Show" or IMS_LEGEND not equal to "No Show". Typically, line features with the "No Show" classification enclose polygon features that are not outlined on a map such as closure lines separating adjacent coastal water polygons or at the data limits.
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 Town Master from USGS is 1:24,000-scale base map data. It depicts all political boundary features published on all of the U.S. Geological Survey (USGS) 7.5-minute topographic quadrangle maps that cover the State of Connecticut. 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. These derived layers either define a subset of polygon and line features for either the geographic area encompassed by all USGS topographic quadrangle maps that cover the State of Connecticut (a master layer) or for the geographic area of the State of Connecticut. The Town Master from USGS layer may also be used as a possible data source for other 1:24,000-scale layers where features must coincide and line up with political boundary features published on the USGS topographic quadrangle maps. Additionally, this layer incorporates coastline and island feature information from the Hydrography Master layer in order to enclose and define the land areas encompassed by towns adjacent to Long Island Sound. The Hydrogaphy Master layer is also published by the Department of Environmental Protection. These Coastline Arc features are commonly used to close polygon features in other 1:24,000-scale layers published by the State of Connecticut, Department of Environmental Protection. For example, Coastline Arcs from the original Hydrography Master layer define the shoreline in the Waterbody, Named Waterbody, Towns, Basins, and Bedrock Geology layers. The Town Master from USGS layer is not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)
USGS Large Scale Digital Line Graph (DLG) data are digital representations of the cartographic (base map) information published on the 1:24,000-scale, 7.5 minute topographic quadrangle maps. The USGS produces DLG data per 7.5 minute quadrangle. DLG data is organized into categories such as hydrography, boundaries, and transportation. At the time the State of Connecticut began developing the Town Master from USGS layer in the late 1980's, Large Scale DLG files were available for 112 of the 115 topographic quadrangle maps necessary to cover Connecticut. Large Scale DLG files were not available for the West Springfield Mass-Conn, Springfield South Mass-Conn, and Hamden Mass-Conn quadrangle. It is important to note that the Large-Scale DLGs were produced in the 1980's at a time when the USGS was developing standards, conventions, and procedures to convert topographic quadrangle maps into digital spatial data. The Connecticut DLG files were produced by digitizing from stable-base Mylars using a digitizing tablet to capture the digital data. The features were manually digitized and attributed. Today, there are other methods available for producing DLGs. For additional DLG documentation, 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.
In the absence of Large Scale DLG data, the USGS provided the State of Connecticut with raster image scans of the Mylar separates used to publish the black, red, brown, and blue inks for 3 of the 115 topographic quadrangle maps that cover Connecticut. These quadrangles include West Springfield Mass-Conn, Springfield South Mass-Conn, and Hamden Mass-Conn.
Town Master features for each quadrangle map. Each quadrangle Town Master layer is in ArcInfo Coverage format.
Hydrography Master is a 1:24,000-scale, polygon and line feature-based layer that includes all hydrography features depicted on all of the U.S. Geological Survey (USGS) 7.5 minute topographic quadrangle maps that cover the State of Connecticut. This data source refers to all Hydrography features combined in one statewide layer. Hydrography Master is in ArcInfo Coverage format.
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
This data source refers to all political boundary features combined in one statewide layer. Since initial publication in 1994, subsequent editions of this master layer were generated by the State of Connecticut in order to change data format, convert from NAD 27 to NAD 83, and improve the quality and accuracy of both feature geometry and feature attribute information. Consequently, over a period of many years, different versions of the layer were produced. Various editions of Town Master from USGS are reflected by those process steps in which the Town Master from USGS layer is identified as both the Source Used and the Source Produced. Town Master from USGS is in ArcInfo Coverage format.
A line feature-based layer representing 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. Town_Master_USGS_Line.shp is in Shapefile format.
A line feature-based layer representing 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. Town_Master_USGS_Line is in Geodatabase Feature Class format.
DLG to ArcInfo coverage format conversion - Using ESRI ArcInfo software, the State of Connecticut, Department of Enviromental Protection converted the (political) boundaries category for each Large Scale DLG file to ArcInfo Coverage format, resulting in one ArcInfo Coverage of polygon and line features for 112 of the 115 quadrangle areas that cover Connecticut. Each Coverage was converted from UTM to Connecticut State Plane, North American Datum of 1927 (NAD27).
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Image to vector (ArcInfo coverage) format conversion - Using ESRI ArcInfo software, the black ink image files that depict the political boundary and other topo map features printed in black on 3 of 115 topographic quadrangle maps were georeferenced to Connecticut State Plane, North American Datum of 1927 (NAD27) by registering the image corners to the corresponding quadrangle corner tics. In an interactive ArcInfo editing environment, the geogreferenced image was displayed in the background in order to visually identify political boundaries that needed to be vectorized (digitized). Features that would have been included in the DLG Political Boundary category by the USGS were were manually digitized on the screen (heads-up digitizing) at display scales greater than 1:24,000. Polygon and line features were assigned TBPOLY_COD and TBARC_COD values based on their cartographic representation on the topographic quadrangle maps. Check plots were produced to inspect digitizing quality and the assignment of TBPOLY_COD and TBARC_COD values.
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Attribute value verification - The quality and accuracy of the digitizing and coding for all features was checked by comparing the features in each ArcInfo Coverage with the state, county, town and borough boundary lines published on the published USGS topographic quadrangle maps. Visual comparisons using 1:24,000-scale paper check plots combined with automated procedures to identify inconsistent attribute coding were the primary means of evaluating and correcting obvious errors with the original DLG data. Where necessary, corrections were made to DLG major and minor codes in the ArcInfo Coverages. The original DLG major and minor codes were replaced by TBPOLY_COD and TBARC_COD attribute in the final Town Master from USGS layer.
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Quadrangle coverage edgematch - Using ESRI ArcInfo software, the individual 7.5 minute quadrangle coverages of Town Master features were systematically edgematched. Line features that cross adjacent quadrangles were moved to make their end-point coordinates identical along quadrangle boundaries through a process of checkerboard style edgematching. Features along the edges of every other quadrangle were adjusted. The ends of poltical boundary lines were snapped to align with the connecting stationary features on adjacent quadrangles if their end-points were generally within 20 feet. Ends of line features were adjusted to match the location of the ends of the corresponding feature on adjacent quadrangles so that features would connect when the quadrangle coverages were appended in the subsequent process step.
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Statewide layer creation - Using ESRI ArcInfo sofware, all (115) 7.5-minute quadrangle coverages were appended to form a single, statewide layer named Town Master from USGS. Linear features were unsplit (merged) to eliminate unnecessary pseudo nodes between similar features from adjacent quadrangle areas. Polygon features were merged across quadrangle boundaries. Polygon features were then manually attributed with the appropriate STATE_COD, FIPS_COD, TOWN_NO, CONN_CITY, and CONN_BORO attribute values. The TOWN attribute is the English equivalent of (decodes) the TOWN_NO polygon attribute and was populated though a table join to a town lookup table. Line features were largely encoded using feature topology-based table joins for assigning values to the STATE_FLG, FIPS_FLG, CONN_FLG, TOWN_FLG, CITY_FLG, BORO_FLG, CNTY_FLG, TNO_LEFT, TOWN_LEFT, TNO_RIGHT, TOWN_RIGHT, CITY_LEFT, and CITY_RIGHT attributes. Additionally, coastline and island feature information from the Hydrography Master layer was incorporated into this layer in order to enclose the land areas encompassed by towns adjacent to Long Island Sound and to define the island polygon features that are part of the land area for coastal towns. Features derived from the Hydrography Master layer are attributed with specific COASTA_COD and COASTP_COD values. The COASTA_COD line attributes for the shoreline features were transferred with the Coastal Arc (coastline) features copied from the Hydrography 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. With the state boundary in Long Island Sound incomplete because most of it is not depicted on USGS topographic quadrangle maps, a boundary line feature representing the state boundary between Connecticut and New York in Long Island Sound was generated using the latitude and longitude coordinates from Source 5 - State boundary coordinates. This line feature was subsequently added to the Town Master for USGS layer. Next, the end points of the state boundary line features offshore Greenwich and Stonington that were based on information from the USGS topographic quadrangle map were tied (moved) to connect to the two end points of the line feature representing the state boundary line between Connecticut and New York in Long Island Sound. This resulted in a fully connected state boundary line feature in Long Island. Additionally, town boundaries separating coastal towns in Long Island Sound are depicted on only some of USGS topographic quadrangle maps. In an attempt to enclose all town polygons in Long Island Sound, portions of the boundaries in Long Island Sound for the following shoreline towns were made to trend due south from their end point as depicted on the USGS topographic quadrangle map until they intersected the Connecticut - New York boundary in the middle of Long Island Sound: Greenwich, Stamford, Darien, Norwalk, Westport, Fairfield, Bridgeport, Stratford, Milford, West Haven, New Haven, East Haven, Branford, Guilford, Madison, Clinton, Westbrook, Old Saybrook, Old Lyme, East Lyme, and Waterford. These particular line features do not represent real town boundaries and are encoded with a TBARC_COD attribute value of zero (0), signifying a Closure Line. In short, all boundary line features are based on the USGS topographic quadrangle maps, with the exception of (1) most of the state boundary in Long Island Sound, which is based on latitude and longitude coordinates and (2) portions of some of the town boundaries in Long Island Sound, which were estimated to trend south from their end point as depicted on the USGS topographic quadrangle map. Final polygon and line feature topology was established with ArcInfo Fuzzy and Dangle tolerances verified at 4 and 10 feet, respectively. At this step in the process the Town Master from USGS layer was fully attributed and ready for use. Not all data fields from the original DLG files were preserved by this step in the process. A new data field, AV_LEGEND, was added to more easily classify and cartographically represent features when mapping and displaying the information with software such as ArcView.
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Datum conversion - Using ESRI ArcInfo software, the Town Master from USGS 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.
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Boundary Correction between Middletown and Portland - The town boundary between Middletown and Portand was changed from its location 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.
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Attribute enhancements - AV_LEGEND, TOWN_POLY, TOWN_ARC, COAST_POLY, and COAST_ARC attributes were modified from storing abbreviated values in upper case to full length values in both upper and lower case. Additionally, the IMS_LEGEND attribute was added to establish a simple feature classification scheme for symbolizing Town Master from USGS features with Internet mapping software environments such as ArcIMS.
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Attribute Integrity Improvements - Using Arc Macro Language (AML), an automated process (MAKECOVER.AML) was developed to maintain consistent attribute values by programmatically joining lookup data tables to decode numeric code fields and encoding the following line attributes based on the topological relationships between the line and polygon features: STATE_FLG, FIPS_FLG, CONN_FLG, TOWN_FLG, CITY_FLG, BORO_FLG, CNTY_FLG, TNO_LEFT, TOWN_LEFT, TNO_RIGHT, TOWN_RIGHT, CITY_LEFT, and CITY_RIGHT. For example, given that each line feature inherently has a (from-to) direction, the value for the TNO_LEFT (Town Number Left) line attribute is based the value of the TOWN_NO (Town Number) attribute for the polygon to the left of the boundary line feature. And the TNO_RIGHT (Town Number Right) line attribute is based the value of the TOWN_NO (Town Number) attribute for the polygon to the right of the boundary line feature. The direction of the line feature is arbitrary and usually reflects the direction with which the feature was digitized. Additionally, the MAKECOVER.AML also encoded Boolean type fields that flag certain types of features such as county boundaries. For example, the CNTY_FLG (Connecticut County Boundary Flag) field stores either a value of "True" or "False" to distinguish county boundaries from other boundaries and is attributed by comparing the value of the CNTY_COD (Connecticut County Code) attribute of the polygon to the left and right of every line feature. If the CNTY_COD polygon attribute values differ, then the line feature is a county boundary and the CNTY_FLG line attribute is assigned a value of "true". In 2005, all Boolean fields such as STATE_FLG, FIPS_FLG, CONN_FLG, TOWN_FLG, CITY_FLG, and BORO_FLG were converted from storing previously used 1 an 0 numeric values to represent true and false conditions to storing "True" and "False" text string values, respectively. The name of the resulting ArcInfo coverage created by this automated process is TOWNUSGS.
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Create 2005 Edition of Town Master from USGS - The automated process (software program), MAKECOVER.AML, developed for the previous process step was executed in 2005 in order to create a 2005 edition (copy) of Town Master From USGS that captures recent corrections and enhancements made to the layer. The MAKECOVER.AML program was last run in 2005, and the name of the resulting ArcInfo coverage created by this automated process is TOWNUSGS.
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Export to Shapefile format - Converted line feature data from an ArcInfo coverage named TOWNUSGS to a Shapefile named Town_Master_USGS_Line.shp. Excluded the FNODE#, TNODE#, LPOLY#, RPOLY#, LENGTH, TOWNUSGS#, and TOWNUSGS-ID attributes from the Shapefile because their values are only maintained by ArcInfo software with data that is in ArcInfo Coverage format. Includes all line features from TOWNUSGS where the AV_LEGEND attribute was not equal to a value of "No Show" (AV_LEGEND <> "No Show"). This selection criterion preserves state, county, town, city, borough boundary and coastine features and excludes Closure Line features, which are quadangle boundaries that define the (outer) data limit of the TOWNUSGS data layer. These Closure Line features, with TBARC_COD attribute values equal to 0 (zero), are not part of Town_Master_USGS_Line.shp.
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Convert to GeoDatabase Feature Class format - Defined new Feature Class named Town_Master_USGS_Line; and imported the attribute definitions, loaded features and imported metadata from Town_Master_USGS_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, Counties and Town on the mainland in in 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 and IMS_LEGEND are broad classifications 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, AV_LEGEND, and IMS_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 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 STATE_COD, FIPS, TOWN_NO, CNTY_COD, CONN_CITY, and CONN_BORO polygon attributes were manually entered and visually inspected and compared to information on the USGS 7.5 minute topographic quadrangle maps. The STATE_FLG, FIPS_FLG, CONN_FLG, TOWN_FLG, CITY_FLG, BORO_FLG, CNTY_FLG, TNO_LEFT, TNO_RIGHT, CITY_LEFT, CITY_RIGHT, AND BOROUGH line attributes were programmatically attributed, basing line attribute values on polygon and line feature topology relationships. 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 Town Master from USGS 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) |
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| 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.
79 Elm Street