This metadata is meant to describe the airport and landing strip data extracted from the USGS 1:24,000 and 1:100,000 scale DLGs (Digital Line Graph). Digital line graph (DLG) data are digital representations of cartographic information. DLG's of map features are converted to digital form from maps and related sources. Both the 1:24,000 and 1:100,000 scale data were combined to create a complete statewide coverage. Data was combined using the most up to date data available at the time of creation. All DLG data distributed by the USGS are DLG - Level 3 (DLG-3), which means the data contain a full range of attribute codes, have full topological structuring, and have passed certain quality-control checks. The files available from NC CGIA are either full dlg3 (USGS approved) or dlgs created by NC CGIA which are under review by the USGS for inclusion in the National database. Both the dlg text files and the ARC/INFO coverages are available from CGIA. For further information on the USGS DLG Project see http://www.usgs.gov
DLG's depict information about geographic features on or near the surface of the Earth, terrain, and political and administrative units. These data were collected as part of the National Mapping Program. NC CGIA digitizes and distributes dlgs to help agencies and others make resource management and other types of decisions.
>system filename: ap24_100 system filesize: .24mb > >Revisions and updates to this layer include: >1)filename: ap24_100_1298 The December 1998 release was the >first release of the combined data.
First CGIA release date
Acknowledgement of products derived form this data set should cite the following: The source of the Airport (1:24,000/1:100,000) data was U.S. Geological Survey and the digital data was obtained from 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.
301 North Wilmington Street, Suite 700
Preferred contact is by email
>United States Geological Survey (USGS) >North Carolina Department of Transportation (NCDOT) >North Carolina Center for Geographic Information and Analysis (NCCGIA) > >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 - airports 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 airports 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 airports, 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 airports and landing strips 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
ARC/INFO, NAD27, Stateplane, feet coverages
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.
1:100,000-scale digital line graph files were mapjoined to form a statewide file for North Carolina representing the Miscellaneous Transmission attributes as shown on the published USGS maps.
301 North Wilmington Street, Suite 700
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Using the current ARC/INFO files both the 1:24,000 and 1:100,000 scale coverages were combined to create a staewide coverage. The final coverage was built for topology and projected to Stateplane meters NAD83.
301 North Wilmington Street, Suite 700
Phone and electronic mail preferred
Metadata imported.
Dataset copied.
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
DLG3 attribute codes are used to describe the physical and cultural characteristics of DLG node, line, and area elements. Attribute codes are used to reduce redundant information, provide enough reference information to support integration with larger data base, and describe the relationships between cartographic elements. Each DLG element has one or more attribute codes composed of a three digit major code and a four-digit minor code. For example, with the 1:24,000-scale DLG data, the line attribute code 190 has a major code (190), meaning miscellaneous transportation features, with a minor code (0403) meaning landing strip, airport, or perimeter of airport. >AP24_100.AAT Arc Attribute Tables >COLUMN ITEM NAME WIDTH OUTPUT TYPE 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 Legth in meters >21 AP24_100# 4 5 B - Internal id >25 AP24_100-ID 4 5 B - Internal id >29 MAJOR1 6 6 I - USGS Major DLG code >35 MINOR1 6 6 I - USGS Minor DLG code >41 SCALE 6 6 I - Base Scale identifier
U.S. Department of the Interior, U.S. Geological Survey, 1987 Digital Line Graphs from 1:24,000-Scale Maps--Data Users Guide 1; Reston, Virginia
Refer to USGS Digital Cartographic Data Standards, circular 895-G for descriptions of the DLG major/minor codes.
301 North Wilmington Street, Suite 700
Phone and electronic mail preferred For current price information use a web browser: COST INFORMATION - http://www.cgia.state.nc.us/cost.html
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