Connecticut Railroads is a 1:24,000-scale, feature-based layer that includes railroad features 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. The layer is based on information from USGS topographic quadrangle maps published between 1969 and 1984 and does not represent the railroad system in Connecticut at any one particular point in time. The layer does not depict current conditions and excludes many railroads that have been built, modified, or removed since the time these topographic quadrangle maps were published. The layer includes railroad tracks, bridges, drawbridges, roundhouses, sidings, tracks, tunnels, underpasses, and stations. It does not include train schedule or track related information. Features are linear and represent railroad track centerlines. Attribute information is comprised of codes to cartographically represent (symbolize) rail features on a map. This layer was originally published in 1994. The 2005 edition includes the same rail 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.
Railroads, Rail Sidings and Railroad Stations as line 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)
Railroad Arc Code. Numeric values that identify railroad feature types. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| 0 | Not Railroad |
| 201 | Railroad |
| 202 | Railroad in Street or Road |
| 204 | Carline |
| 208 | Railroad Siding |
| 209 | Perimeter or Limit of yard |
| 400 | Perimeter of Railroad Station |
| 402 | Roundhouse |
| 2201 | Two Track Railroad |
| 4201 | Four Track Railroad |
| 209201 | Railroad, Perimeter or Limit of Yard |
| 209208 | Railroad Siding, Perimeter or Limit of Yard |
| 601201 | Railroad, in Tunnel |
| 601208 | Railroad Siding, in Tunnel |
| 602201 | Railroad, Overpassing on Bridge |
| 602208 | Railroad Siding, Overpassing on Bridge |
| 603201 | Railroad, Abandoned |
| 603208 | Railroad Siding, Abandoned |
| 605201 | Railroad, Underpassing |
| 605202 | Railroad in Street or Road, Underpassing |
| 605208 | Railroad Siding, Underpassing |
| 605210 | Arbitrary Line Extension, Underpassing |
| 606208 | Railroad Siding, Narrow Gauge |
| 607201 | Railroad, in Snowshed or under Structure |
| 607208 | Railroad Siding, in Snowshed or under Structure |
| 611201 | Railroad, on Drawbridge |
| 611202 | Railroad in Street or Road, on Drawbridge |
| 4209201 | Four Track Railroad, Perimeter or Limit of Yard |
| 4602201 | Four Track Railroad, Overpassing on Bridge |
| 4605201 | Four Track Railroad, Underpassing |
| 4611201 | Four Track Railroad, on Drawbridge |
| 605603201 | Railroad, Abandoned, Underpassing |
| 605603208 | Railroad Siding, Abandoned, Underpassing |
Railroad Class. Text values that correspond to the numeric RRARC_COD attribute values. RAIL_CLASS is the English language equivalent of (decodes) the RRARC_COD field. (Source: State of Connecticut, Department of Environmental Protection)
ArcView Legend. Text field for symbolizing railroad feature types on a map. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| Abandoned | This category includes RRARC_COD values 603201, 603208, 605603201, 605603208. |
| Bridge | This category includes RRARC_COD values 602201 and 602208. |
| Drawbridge | This category includes RRARC_COD values 611201, 611202 and 4611201. |
| Narrow Gauge | This category includes RRARC_COD value 606208. |
| Roundhouse | This category includes RRARC_COD value 402. |
| Siding | This category includes RRARC_COD values 208, 209208, and 607208. |
| Track | This category includes RRARC_COD values 201, 202, 204, 2201, 4201, 209201, 607201, 4209201, and 4602201. |
| Tunnel | This category includes RRARC_COD values 601201 and 601208. |
| Underpass | This category includes RRARC_COD values 605201, 605202, 605208, 605210, and 4605201. |
| Station | This category includes RRARC_COD values 209 and 400. |
Internet Mapping Software Legend. Text field for symbolizing railroad feature types on an Internet map. (Source: State of Connecticut, Department of Environmental Protection)
| Value | Definition |
|---|---|
| Abandoned | This category includes RRARC_COD values 603201, 603208, 605603201, and 605603208. |
| Siding | This category includes RRARC_COD values 208, 209208, and 607208. |
| Station | This category includes RRARC_COD values 209, 400 and 402. |
| Track | This category includes RRARC_COD values 201, 202, 204, 2201, 4201, 601201, 601208, 605201, 605202, 605208, 605210, 606208, 607201, 611201, 611202, 4209201, 4602201, 4605201, and 4611201. |
Includes linear railroad features such as includes railroad tracks, bridges, drawbridges, roundhouses, sidings, tracks, tunnels, underpasses, and stations published on the U.S. Geological Survey 7.5 minute topographic quadrangle maps. Information encoded about features includes railroad feature type classification, and two standard symbology classification schemes.
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 Railroads is 1:24,000-scale base map data. It depicts the location of all railroads trails published on the USGS topographic quadrangle maps. For base map purposes, use this layer with other 1:24,000-scale base map data such as Hydrography, Roads and Trails, Airports, and Towns. The Railroads layer includes information within Connecticut and is derived from the Railroads Master layer, which includes all railroad 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 may be used as a possible data source for other 1:24,000-scale layers having features that should coincide with railroad tracks on the 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.)
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 Railroads 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.
Railroad features for each quadrangle map.
Railroad features for Connecticut combined in a single, statewide layer. Railroad is in ArcInfo Coverage format.
Railroad features for Connecticut combined in a single, statewide layer. Railroad.shp is in Shapefile format.
Railroad features for Connecticut combined in a single, statewide layer. Railroad 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 Railroad overlay from the Transporation category for each Large Scale DLG file to ArcInfo Coverage format, resulting in one ArcInfo Coverage of linear features for each quadrangle area. The Transportation category of data includes major transportation systems collected in three separate overlays labeled: (1) Roads and Trails, (2) Railroads, and (3) Pipelines, Transmission Lines, and Miscellaneous Transportation Features. Only the Railroad overlay was extracted from the Transportation Layer as a data source for this layer. 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 railroad (and road and trail features) on three 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 railroad track features were visually identified on the background image and manually vectorized. Railroad features that would have been included in the DLG Transportation category by the USGS were were manually digitized on the screen (heads-up digitizing). Features were assigned RRARC_COD values based on their cartographic representation on the topographic quadrangle maps. Check plots were made to inspect digitizing quality and the assignment of RRARC_COD values.
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Attribute value verification - The quality and accuracy of the digitizing and coding of the railroad features was checked by comparing the transporation features in each ArcInfo Coverage with the railroad features 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 modified to form the RRARC_COD attribute in the final Railroads layer.
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Quadrangle coverage edgematch - Using ESRI ArcInfo software, the individual 7.5 minute quadrangle coverages of Railroad features were systematically edgematched. Features along the edges of adjacent quadrangle were moved to make their end-point coordinates identical through a process of checkerboard style edgematching. Features on every other quadrangle were adjusted. The ends of Railroad segments were snapped to align with the connecting stationary features on adjacent quadrangles if their end-points were generally within 20 feet. On occasion, there were no connecting features on adjacent quadrangles to match to so some features abruptly end at quadrangle boundaries. This is mostly due to variations in quadrangle publication dates. Varying publication dates also explain inconsistent DLG major and minor codes for certain railroads that appear on more than one topographic map. For example, a track that appears on two adjacent quadrangle maps may appear as a track on one map and abandoned track on the adjacent (more recent) map. Consequently, RRARC_COD values for some railroad tracks change when crossing quadrangle boundaries. These inconsistencies were not resolved because the intent was to represent the classification of these features on USGS topographic quadrangle maps.
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Statewide layer creation - Using ESRI ArcInfo sofware, all of individual 7.5 minute quadrangle coverages were appended to form a single, statewide Railroads layer. Linear features were unsplit (merged) to eliminate unnecessary pseudo nodes between similar features from adjacent quadrangle areas. Final 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 Railroads layer was fully attributed and ready for use. Not all data fields from the orginal 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 displaying the information with software such as ArcView.
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Datum conversion - Using ESRI ArcInfo software, the Railroads 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 - RAIL_CLASS and AV_LEGEND attributes were changed from storing abbreviated values in upper case (e.g. TRACK, SIDING, STATION ) to full length values in both upper and lower case (e.g. Track, Siding, Station). Additionally the IMS_LEGEND attribute was added to establish a very general classification scheme for symbolizing railroad features with Internet mapping software environments such as ArcIMS. The following attributes from the original DLG files were removed from the data table due to poor data quality: PHOTRV_FLG and QUAD_NO. These attribute values were inconsistent, not verified and of limited value to the State of Connecticut. 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 Railroads layer that is clipped to the State of Connecticut boundary.
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Create 2005 Edition of Railroad - 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 Railroad 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 RAIL. Note, this particular run of the MAKECOVER.AML created a copy of the Railroad ArcInfo coverage that is clipped to the State of Connecticut boundary and is named RAIL instead of RAILMASTER. Prior to 2005, the Railroads layer in ArcInfo Coverage format that was clipped to the state of Connecticut boundary was named RAILROADCT.
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Export to Shapefile format - Converted line feature data from an ArcInfo coverage named RAIL to a Shapefile named Railroad.shp. Excluded the FNODE#, TNODE#, LPOLY#, RPOLY#, LENGTH, RAIL#, RAIL-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 Railroad; and imported the attribute definitions, loaded features and imported metadata from Railroad.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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The layer retains the feature types identified by the USGS. All attributes have valid values. Values are within defined domains. The accuracy test for the RRARC_COD attribute values was conducted by comparing the railroads published on the source topographic quadrangle maps with 1:24,000-scale check plots or interactive displays of the railroads data on a computer graphic system. These checkplots and computer displays depicted the railroad features in different colors based on their respective RRARC_COD values for comparison with the paper quadrangle maps. The RAIL_CLASS, AV_LEGEND, and IMS_LEGEND attribute values are based on RRARC_COD values. RAIL_CLASS decodes the RRARC_COD field. AV_LEGEND and IMS_LEGEND are broad classifications of RRARC_COD values. The RAIL_CLASS, AV_LEGEND, and IMS_LEGEND fields were populated though table joins to lookup tables. These values were not manually entered.
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 Railroads 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 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 Railroads layer. So compared to the most recent set of topographic quadrangle maps available today, the Railroads layer is incomplete, and substantially incomplete when compared to the railroad system 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. The tests of logical consistency were performed by the USGS PROSYS program, and subsequently 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: Railrods - From the Railroads 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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