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Connecticut Railroads Master

Frequently-asked questions:


What does this data set describe?

Title:
Connecticut Railroads Master

Abstract:
Connecticut Railroads Master is a 1:24,000-scale, feature-based layer that 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. 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.

Supplemental information:
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.

  1. How should this data set be cited?

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

    Online links:
    Other citation details:
    The USGS is the collector of the data (compiler). The State of Connecticut, Department of Environmental Protection is the creator and maintainer of the data layer (editor) and producer (publisher) of this information for use. The 2005 Edition essentially includes the same set of geographic features published in 1994. However, the 2005 Edition differs from information published in 1994 primarily as a result of corrections and improvements to feature geometry and feature attribute information. Previously undetected errors have been corrected. Also, some feature attribute information (data fields) have been slightly modified and made easier to use. Except for periodic corrections, this layer includes information that is relatively static and does not change over time. Data compiled at 1:24,000 scale.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -73.767940
    East: -71.738223
    North: 42.128490
    South: 40.942283

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/railroadmasterfullview.gif (GIF)
    Full view of Connecticut Railroads Master. These data include nearby railroads in Massachusetts, New York and Rhode Island published on the USGS 7.5 minute topographic maps that cover Connecticut.

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/railroadmasterdetailview.gif (GIF)
    Detail view of Connecticut Railroads Master within the vicinty of New Haven, Connecticut. These railroad features are based on information published on USGS 7.5 minute topographic quadrangle maps.

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

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

  5. What is the general form of this data set?

    Geospatial data presentation form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      Indirect spatial reference:
      State of Connecticut, United States of America

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • String (4552)

    2. What coordinate system is used to represent geographic features?

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Lambert Conformal Conic
      Standard parallel: 41.200000
      Standard parallel: 41.866667
      Longitude of central meridian: -72.750000
      Latitude of projection origin: 40.833333
      False easting: 999999.999996
      False northing: 499999.999998

      Planar coordinates are encoded using coordinate pair.
      Abscissae (x-coordinates) are specified to the nearest 0.000250.
      Ordinates (y-coordinates) are specified to the nearest 0.000250.
      Planar coordinates are specified in survey feet.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical coordinate system definition:
      Altitude system definition:
      Altitude resolution: 1.000000
      Altitude encoding method: Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    Connecticut Railroads Master
    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)

    OBJECTID
    Internal feature number. (Source: ESRI)
                      

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    RRARC_COD
    Railroad Arc Code. Numeric values that identify railroad feature types. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    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

    RAIL_CLASS
    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)
                      

    See Enumerated Domain Value Definitions for RRARC_COD attribute.

    AV_LEGEND
    ArcView Legend. Text field for symbolizing railroad feature types on a map. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    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.

    IMS_LEGEND
    Internet Mapping Software Legend. Text field for symbolizing railroad feature types on an Internet map. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    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.

    SHAPE.len
    Entity and attribute overview:
    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.

    Entity and attribute detail citation:
    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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Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)


  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Howie Sternberg
    State of Connecticut, Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106-5127
    USA

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

Connecticut Railroads Master 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 Master, Roads and Trails Master, Airports Master, and Towns Master. 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.)

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How was the data set created?

  1. Where did the data come from?

    Source 1 - DLG (source 1 of 6)

    U.S. Geological Survey, National Mapping Program (data compiler and publisher), 1969-1984, USGS Large Scale Digital Line Graph (DLG): U.S. Geological Survey, Reston, Virginia, USA.

    Type of source media: digital tape media
    Source scale denominator: 24000
    Source contribution:
    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.

    Source 2 - Quadrangle image data (source 2 of 6)

    U.S. Geological Survey, National Mapping Program (data compiler), Unpublished Material, Scanned USGS Topographic Quadrangle Map Mylars: U.S. Geological Survey, Reston, Virginia, USA.

    Type of source media: digital tape media
    Source scale denominator: 24000
    Source contribution:
    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.

    Source 3 - Quadrangle data (source 3 of 6)

    State of Connecticut, Department of Environmental Protection (data editor), U.S. Geological Survey, National Mapping Program (data compiler), Unpublished Material, Railroad 7.5 minute quadrangle Coverages: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Railroad features for each quadrangle map.

    Source 4 - Railroad (source 4 of 6)

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

    Online links:
    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Railroad features for all Connecticut quadrangle maps combined in a single, statewide layer. Railroad is in ArcInfo Coverage format.

    Source 5 - Railroad_Master.shp (source 5 of 6)

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

    Online links:
    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Railroad features for all Connecticut quadrangle maps combined in a single, statewide layer. Railroad_Master.shp is in Shapefile format.

    Source 6 - Railroad_Master (source 6 of 6)

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

    Online links:
    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Railroad features for all Connecticut quadrangle maps combined in a single, statewide layer. Railroad_Master is in GeoDatabase Feature Class format.

  2. What changes have been made?

    Date: 1985-1987 (change 1 of 10)
    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).

    Person responsible for change:
    Deborah Dumin, Jonathan Scull
    State of Connecticut, Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106
    USA

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 1 - DLG

    Data sources produced in this process:
    • Source 3 - Quadrangle data

    Date: 1988 (change 2 of 10)
    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.

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 2 - Quadrangle image data

    Data sources produced in this process:
    • Source 3 - Quadrangle data

    Date: 1985-1988 (change 3 of 10)
    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.

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 3 - Quadrangle data

    Data sources produced in this process:
    • Source 3 - Quadrangle data

    Date: 1989-1990 (change 4 of 10)
    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.

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 3 - Quadrangle data

    Data sources produced in this process:
    • Source 3 - Quadrangle data

    Date: 1994 (change 5 of 10)
    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.

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 3 - Quadrangle data

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

    Date: 1999 (change 6 of 10)
    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.

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 4 - Railroad

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

    Date: 2001-2004 (change 7 of 10)
    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.

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 4 - Railroad

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

    Date: 2005 (change 8 of 10)
    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 RAILMASTER.   Prior to 2005, the Railroads Master layer in ArcInfo Coverage format was named RAILROAD.

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 4 - Railroad

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

    Date: 2005 (change 9 of 10)
    Export to Shapefile format - Converted line feature data from an ArcInfo coverage named RAILMASTER to a Shapefile named Railroad_Master.shp. Excluded the FNODE#, TNODE#, LPOLY#, RPOLY#, LENGTH, RAILMASTER#, RAILMASTER-ID attributes from the Shapefile because their values are only maintained by ArcInfo software with spatial data that is ArcInfo coverage format.

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 4 - Railroad

    Data sources produced in this process:
    • Source 5 - Railroad_Master.shp

    Date: 2006 (change 10 of 10)
    Convert to GeoDatabase Feature Class format - Defined new Feature Class named Railroad_Master; and imported the attribute definitions, loaded features and imported metadata from Railroad_Master.shp shapefile. 
    
    Spatial Reference Properties for Feature Class:
    
    Coordinate System: NAD_1983_StatePlane_Connecticut_FIPS_0600_Feet
    XY Domain MinX: 100000; MaxX: 2247483.645
    XY Domain MinY: 200000; MaxY: 2347483.645
    Precision: 1000

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

    860-424-3540 (voice)

    Data sources used in this process:
    • Source 5 - Railroad_Master.shp

    Data sources produced in this process:
    • Source 6 - Railroad_Master

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

  1. How well have the observations been checked?

    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.

  2. How accurate are the geographic locations?

    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.

  3. How accurate are the heights or depths?

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

    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 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 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 railroad system in existence today. This data is not updated.

  5. How consistent are the relationships among the observations, including topology?

    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).

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How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access constraints: None. The data is in the public domain and may be redistributed.
Use constraints:
No restrictions or legal prerequisites for using the data. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet). Although this data set  has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Department of Environmental Protection and the U.S. Geological Survey, National Mapping Program as the source for this information. For example, include the following data source description when printing this layer on a map: Railroads - From the Railroads Master layer, compiled and published by CT DEP and USGS. Source map scale is 1:24,000.

Distributor 1 of 1

  1. Who distributes the data set?

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

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

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

    Connecticut Railroads Master

  3. What legal disclaimers am I supposed to read?

    Although this data set  has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Environmental Protection as to the accuracy of the data and or related materials.  The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata.

  4. How can I download or order the data?

    • Availability in digital form:


    • Data format:
      in format Shapefile, Feature Class, ArcInfo Coverage (version ArcGIS)
      Network links:http://www.ct.gov/deep

    • Cost to order the data: An online copy of the data may be accessed without charge.


  5. Is there some other way to get the data?

    The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving the data.

  6. What hardware or software do I need in order to use the data set?

    Geographic information sytem (GIS), computer-aided drawing or other mapping software is necessary to display, view and access the information.

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Who wrote the metadata?

Dates:
Last modified: 20111208

Metadata author:
Howie Sternberg
State of Connecticut, Department of Environmental Protection
79 Elm Street
Hartford, Connecticut 06106-5127
USA

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

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata(FGDC-STD-001-1998)

Metadata extensions used:
  • http://www.esri.com/metadata/esriprof80.html

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