The US Geological Survey-National Mapping Division created the 1:100,000-scale Railroads data from their published maps. The 1:24,000 scale railroads were derived from USGS's DLG (Digital Line Graph) Program The NC Center for Geographic Information and Analysis, combined these two data sources to develop the NC statewide Transportation-Railroads digital data as a base layer showing railroad features. 24 k data was use when duplicate tracks existed from both sources.
This data was created to assist governmental agencies and others in making resource management decisions through use of a Geographic Information System (GIS).
Refer to "USGS Digital Cartographic Data Standards," circular 895-G for USGS Coding Classification. Also, see www.usgs.gov for further information on the DLG Program. >system filename : rr24_100 approx. file size = 2.4 mb > >Revisions and updates to this layer include: >3) filename: rr24_1001298 - the December, 1998 release of this >data was the first release as a statewide combined file. This >file is a combination of the 24 k dlg data previously stored >by quad tile, and the 100k statewide rail file from the 100k >dlg data. >2) filename: rrt10098 This is the 100k rail only (superceded >by the combined file) in the 83/sp/m projection. This was >performed in 1998. This is a statewide file. >3) filename: rrt10087 The 1987 version was the first release >of the 100k rail data. This is a statewide file.
First CGIA release date.
Acknowledgement of products derived from this data set should cite the following: The source of the Transportation- Railroads (1:24,000/1:100,000) data is the North Carolina Corporate Geographic Database. Earlier versions of this dataset may exist. The user must be sure to use the appropriate data set for the time period of interest. While efforts have been made to ensure that these data are accurate and reliable within the state of the art, CGIA cannot assume liability for any damages or misrepresentation caused by any inaccuracies in the data or as a result of changes to the data caused by system transfers.
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Preferred contact is by email
>US Geological Survey (USGS) >North Carolina Department of Transportation (NCDOT) > >NCCGIA Director, Karen Siderelis >Database Administration, Zsolt Nagy >Database Management, Ken Shaffer >North Carolina Center for Geographic Information and Analysis >Governor's Office >Office of State Planning >301 North Wilmington Street, Suite 700 >Raleigh, NC 27601-2825
The digital line graphs (DLGs)for transportation - railroads were delineated on USGS 1:100,000-scale topographic maps and 1:24,000 scale topographic maps and attributed with USGS DLG codes. The digital files were supplied to NC CGIA who edits the attributes as changes occur. The two datasets were merged to fill in gaps that occured in both datasets allowing for a more complete statewide railroad coverage.
Using ESRI's ARC/INFO GIS software, the data set was built for arc topology using the "build" command. Topology has not been edited since the last build.
These data represent transportation features for railroads, as determined by the US Geological Survey 1:100,000-scale Digital Line Graph program and 1:24,000-scale Digital Line Graph program. Each feature is attributed with various DLG codes. Data represent all known railroads at time of publication of sources.
Features were delineated on USGS 30 x 60 Minute and 7.5 minute series topographic maps, which meet National Map Accuracy Standards. The DLGs were digitized and supplied to NC CGIA who converted them into ARC/INFO format. The data was projected, and features are added as changes occur.
spatial and attribute information
Digital Line Graphs
For Digital Revision Status = Not digitally revised: This Digital Line Graph was digitized from the USGS source quadrangle, by either the National Mapping Division, one of their cooperators, or one of their contractors. The digital data were produced by one of the following methods: - scanning a stable-based copy of the graphic materials. The scanning process captured the digital data at a scanning resolution of at least 0.001 inches; the resulting raster data were vectorized and then attributed on an interactive editing station. o scanning the paper map. The scanning process captured the digital data at a scanning resolution of at least 0.001 inches; the resulting raster data were vectorized and then attributed on an interactive editing station. - scanning a stable-based copy of the graphic materials. The resulting raster data were then manually digitized and attributed on an interactive editing station. The resolution of the digital data is at least 0.001 inches. o scanning the paper map. The resulting raster data were then manually digitized and attributed on an interactive editing station. The resolution of the digital data is at least 0.001 inches. - manually digitizing from a stable-based copy of the graphic material using a digitizing table to capture the digital data at a resolution of at least 0.001 inches; attribution was performed either as the data were digitized, or on an interactive edit station after the digitizing was completed. - manually digitizing from the paper map using a digitizing table to capture the digital data at a resolution of at least 0.001 inches; attribution was performed either as the data were digitized, or on an interactive edit station after the digitizing was completed. The determination of the DLG production method was based on various criteria, including feature density, feature symbology, and availability of production systems. Four control points corresponding to the four corners of the quadrangle were used for registration during data collection. An eight parameter projective transformation was performed on the coordinates used in the data collection and editing systems to register the digital data to the internal coordinates used in PROSYS, and a four parameter linear transformation was performed from the PROSYS internal coordinates to Universal Transverse Mercator (UTM) grid coordinates. The DLG data were checked for position by one or more of the following processes: - comparing plots of the digital data to the graphic source. - comparing the digital data to the digital raster scan. DLG data classification was checked by at least one of the following processes. - comparing plots of the digital data to the graphic source - comparing the digital data to the digital raster scan.
NCCGIA received the dlg linework for the railroads from the USGS in a digital format. These files were refined at NCCGIA, including edgematching, deletion of neatlines. Errors in dlg label codes or inconsistencies in label order are corrected as they are found. Additional linework is added as needed. The 24,000 and 100,000 scale data was combined into one statewide file for ease of use.
301 North Wilmington Street, Suite 700
Phone and electronic mail preferred
Metadata imported.
Internal feature number.
ESRI
Feature geometry.
ESRI
Internal number of poly to left of arc
Software computed
Internal number of poly to right of arc
Software computed
Length of arc in coverage units
Software computed
Internal feature number
Software computed
Internal identification number
User defined
Major DLG numeric code
USGS
Minor DLG numeric code
USGS
Scale of feature source
The scale denominator of the feature source
Source is 1:100,000-scale dlgs
NC CGIA
Source is 1:24,000-scale dlgs
NC CGIA
An arc coverage depicting the locations of railroads mapped in both 1:24,000 and 1:100,000 scales delineated by the US Geological Survey. The arc attribute table (AAT) has data including to- and from-node identifiers, left- and right- side polygon identifiers, length of linear feature in meters, and two internal identification numbers. There are three additional items, which describe the features, according to USGS Digital Line Graph codes, as well as a base map scale attribute. >COLUMN ITEM NAME WDTH OPUT TYP N.DEC ALTERNATE NAME >1 FNODE# 4 5 B - From node id >5 TNODE# 4 5 B - To node id >9 LPOLY# 4 5 B - Left poly id >13 RPOLY# 4 5 B - Right poly id >17 LENGTH 4 12 F 3 Length in meters >21 RR24_100# 4 5 B - Internal id >25 RR24_100-ID 4 5 B - Internal id >29 MAJOR1 6 6 I - USGS DLG code >35 MINOR1 6 6 I - USGS DLG code >41 SCALE 6 6 I - Base map scale
Refer to USGS Digital Cartographic Data Standards, circular 895-G for descriptions of the DLG major/minor codes.
301 North Wilmington Street, Suite 700
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NCCGIA is charged with the development and maintenance of the State's corporate geographic database and, in cooperation with other mapping organizations, is committed to offering its users accurate, useful, and current information about the state. Although every effort has been made to ensure the accuracy of information, errors and conditions originating from physical sources used to develop the corporate database may be reflected in the data supplied. The client must be aware of data conditions and bear responsibility for the appropriate use of the information with respect to possible errors, original map scale, collection methodology, currency of data, and other conditions specific to certain data. NCCGIA does not support secondary distribution of this data. The use of trade names or commercial products does not constitute their endorsement by the NCCGIA or North Carolina State Government.
Data creation and large data analysis jobs contact Database Administration P:(919)733-2090. All data is available through standard ordering procedures on a cost recovery basis.
301 North Wilmington Street, Suite 700
Phone and electronic mail preferred