Connecticut Buffered Roads is a 1:24,000-scale, feature-based layer of paved and unpaved roads on the U.S. Geological Survey (USGS) 7.5 minute topographic quadrangle maps for the State of Connecticut. This layer only includes features located in Connecticut. This layer is cartographic in nature. It is designed to be used with maps printed at 1:24,000-scale that require road symbology similar to the standard established by the USGS for 1:24,000-scale, 7.5 minute topographic quadrangle maps. Two layers, the Buffered Roads layer and the Roads and Trails layer, are used together for this purpose. Buffered Roads features are linear and run parallel to the road (centerline) features of the Roads and Trails layer. Buffered Roads is a set of parallel lines 50 feet apart that result from a buffer on each side of the Road and Trail (centerline) features by a distance of 25 feet. A width of 50 feet is applied to all roads, regardless of road class, and does not reflect actual pavement width. The Buffered Roads layer does not include features on the topographic quadrangle maps that appear as single lines such as hiking trails, small private roads, and old railroad grades. These features are found in the more complete Roads and Trails layer. The Buffered Roads layer is derived from information from USGS topographic quadrangle maps published between 1969 and 1984 and does not represent the road network in Connecticut at any one particular point in time. The layer does not depict current conditions and excludes many roads that have been built, modified, or removed since the time these topographic quadrangle maps were published. The layer includes buffered centerlines for Interstate highways, US routes, state routes, local roads, unpaved roads, traffic circles, bridges, cul-de-sacs, etc. Trails are not included. Features are linear and approximate road curb lines at 1:24,000 scale. Attribute information is comprised of codes to cartographically represent (symbolize) paved and unpaved roads on a map. This layer was originally published in 1994. The 2005 edition includes the same road features published in 1994, but the attribute information has been slightly modified and made easier to use.
In 2004, the State of Connecticut Department of Environmental Protection developed automated procedures to systematically maintain feature topology and attribute integrity for a set of related transportation data produced by the agency during the 1980's and 1980's from the 1:24,000-scale USGS DLGs. These layers include Roads and Trails Master, Roads and Trails, Railroads Master, Railroads, Buffered Roads Master, Buffered Roads, Airports Master, and Airports. Automated procedures were developed using ArcInfo Workstation 8.3 software and the Arc Macro Language (AML) as a scripting environment and recorded in an AML file named MAKECOVER.AML for the transportation category of data for 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.
Publication dates of the USGS 7.5 minute topographic quadrangle maps for the State of Connecticut through 1984.
Paved and unpaved roads as features (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)
Buffered Road Code. Numeric values that classify buffered roads into two groups for symbology purposes so paved and unpaved roads are outlined with solid and dashed lines, respectively. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| 1 | Unpaved |
| 2 | Paved |
Buffered Road Class. Text values that correspond to the numeric ROBUFF_COD attribute values. BUFFERED is the English language equivalent of (decodes) the ROBUFF_COD field. (Source: State of Connecticut, Department of Environmental Protection)
ArcView Legend. Text field for symbolizing buffered roads on a map. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| Dashed | This category includes ROBUFF_COD value 1. |
| Solid | This category includes ROBUFF_COD value 2. |
Includes line features that border both the left and right sides of highways, routes, local roads, unpaved roads, traffic circles, bridges, cul-de-sacs published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps. Information encoded about these features indicates whether these appear as solid or dashed black lines on the published topographic quadrangle maps.
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 Buffered Roads is 1:24,000-scale base map data. This layer is intended to be used with the Roads and Trails layer to reproduce the cartographic symbology established by the USGS for printing roads and trails on the 1:24,000-scale, 7.5-minute topographic quadrangle maps. Cartographically, the Buffered Roads layer is used to assign thin, black line symbology to the edges or curb lines of paved and unpaved roads on the quadrangle maps. Paved roads are symbolized with a narrow solid black line. Unpaved roads are symbolized with a narrow dashed black line. Complementing this symbology, the Roads and Trails layer is used to assign line symbology that 'fills in' the corresponding buffered road area with solid red or dashed red line work, depending on road class. Line symbology should be assigned to Roads and Trails features with AV_LEGEND attribute values equal to Primary Route (wide solid red), Secondary Route (wide dashed red), and Trail (narrow dashed black). Used in combination, Buffered Roads symbology outlines the centerline-based symbology applied to the Roads and Trails layer. For base map purposes, use this layer with other 1:24,000-scale base map data such as Hydrography, Railroads, Airports, and Towns. The Buffered Roads layer includes information within Connecticut and is derived from the Buffered Roads Master layer, which reproduces all buffered road features depicted on all of the U.S. Geological Survey (USGS) 7.5 minute topographic quadrangle maps that cover the State of Connecticut. This layer is a cartographic product and should only be printed on maps at 1:24,000 scale (1 inch = 2,000 feet.).
Road and Trail features for Connecticut combined in a single, statewide layer.
This source is derived from the Roads and Trails layer. It is the basis for the paved road lines in the Buffered Roads layer. This is an intermediate data source that was deleted once the feature information was incorporated into the layer that combined both paved and unpaved buffered roads.
This source is derived from the Roads and Trails layer. It is the basis for the unpaved road lines in the Buffered Roads layer. This is an intermediate data source that was deleted once the feature information was incorporated into the layer that combined both paved and unpaved buffered roads.
Buffered Road features for Connecticut combined in a single, statewide layer. Buffered Road is in ArcInfo Coverage format.
Buffered Road features for Connecticut combined in a single, statewide layer. Buffered_Road.shp is in Shapefile format.
Buffered Road features for Connecticut combined in a single, statewide layer. Buffered_Road is in GeoDatabase Feature Class format.
Paved Roads Buffer - Using ESRI ArcInfo software, the following features from the Roads and Trails layer were buffered 25 feet to create an ArcInfo coverage with line features for buffered paved roads. Class 1, 2, and 3 roads, streets, bridges, and connectors with ROARC_COD values equal to 5, 201, 202, 203, 204, 205, 206, 207, 209, 217, 218, 401, 402, 401201, 401205, 401209, 402201, 601202, 604203, 610205, 610209, 618201, 618205, 618209, and 621201. A ROBUFF_COD attribute value of 1 was assigned to all of these paved buffered road line features.
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Unpaved Roads Buffer - Using ESRI ArcInfo software, the following features from the Roads and Trails layer were buffered 25 feet to create an ArcInfo coverage with line features of buffered unpaved roads. Class 4 roads and streets, old railroad grades and private roads with ROARC_COD values equal to 210, 605210, and 610210. A ROBUFF_COD attribute value of 2 was assigned to all of these unpaved buffered road line features.
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Buffered Roads layer creation - Using ESRI ArcInfo software, the paved buffered roads and unpaved buffered roads layers were merged into a single ArcInfo coverage. By creating temporary polygon features to programmatically identify and delete the half round ends of paved roads inside (intersecting) unpaved buffered roads and half round ends of paved roads inside (intersecting) upaved buffered roads, continuously smooth patterns of buffered lines for paved and unpaved roads were generated. These line features retained original ROBUFF_COD attribute values of 1 or 2 to distinguish paved from unpaved roads.
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Datum conversion - Using ESRI ArcInfo software, the Roads 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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Attribute enhancements - BUFFERED and AV_LEGEND attributes were changed from storing upper case values (e.g. PAVED, UNPAVED) to both upper and lower case values (e.g. Paved, Unpaved). 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. The MAKECOVER.AML also created this particular copy of the Buffered Roads layer that is clipped to the State of Connecticut boundary.
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Create 2005 Edition of Buffered Road - 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 Buffered Road 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 ROADBUF. Note, this particular run of the MAKECOVER.AML created a copy of the Buffered Road ArcInfo coverage that is clipped to the State of Connecticut boundary and is named ROADBUF instead of ROADMBUFMASTER. Prior to 2005, the Buffered Roads layer in ArcInfo Coverage format that was clipped to the state of Connecticut boundary was named ROADBCT.
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Export to Shapefile format - Converted line feature data from an ArcInfo coverage named ROADBUF to a Shapefile named Buffered_Road.shp. Excluded the FNODE#, TNODE#, LPOLY#, RPOLY#, LENGTH, ROADBUF#, ROADBUF-ID attributes from the Shapefile because their values are only maintained by ArcInfo software with spatial data that is ArcInfo coverage format.
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Convert to GeoDatabase Feature Class format - Defined new Feature Class named Buffered_Road; and imported the attribute definitions, loaded features and imported metadata from Buffered_Road.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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All attributes have valid values. Values are within defined domains. The accuracy of the ROBUFF_COD attribute values was spot checked by comparing 1:24,000-scale checkplots with the actual quadrangle maps, and using interactive computer graphic displays to compare Buffered Roads features with Roads and Trails features. These checkplots and computer displays depicted the paved and unpaved buffered roads edge lines in different colors based on their respective ROBUFF_COD values. These tests were visual. No manual edit corrections were necessary. The BUFFERED and AV_LEGEND attribute values are based on ROBUFF_COD values. BUFFERED decodes the ROBUFF_COD field. AV_LEGEND is a classification of ROBUFF_COD values. The BUFFERED and AV_LEGEND fields were populated though table joins to lookup tables. These values were not manually entered.
When printed and displayed at 1:24,000 scale, this data can be considered to come close to complying 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 buffered road lines are software generated from the Roads and Trails layer, which complies with this horizontal accuracy standard, and when displayed at 1:24,000 scale, the buffered road lines line up with the black lines edging the roads on the USGS 7.5 minute topographic quadrangle maps.
The completeness of the data reflects the feature content of the Roads and Trails layer, which is the basis for the Buffered Roads layer. The Roads and Trails layer is based on information available from the USGS for the 1:24,000-scale topographic quadrangle maps published between 1969 and 1984. For details refer to the Roads and Trails layer metadata. The Buffered Roads layer 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 Roads and Trails layer. Some newer quadrangle maps have been published by the USGS since 1984, however, the State of Connecticut did not incorporate this information into the layer. So compared to the most recent set of topographic quadrangle maps available today, the layer is incomplete, and substantially incomplete when compared to the network of highways and streets in existence today. This data is not updated.
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. All lines are software generated using ESR ArcInfo software to buffer selected road features from the Roads and Trails layer by 25 feet. 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 verified line feature topology and enforced a minimum distance between vertices of 4 feet (fuzzy tolerance) and no minimum allowed overshoot length (dangle length = 0).
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: Roads - From the Buffered Roads 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, 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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