Liner Notes

Description

The National Transportation Atlas Databases 2012 (NTAD2012) is a set of nationwide geographic databases of transportation facilities, transportation networks, and associated infrastructure. These datasets include spatial information for transportation modal networks and intermodal terminals, as well as the related attribute information for these features. Metadata documentation, as prescribed by the International Organization of Standards (ISO), is also provided for each database. The data on this DVD support research, analysis, and decision-making across all modes of transportation. They are most useful at the national level, but have major applications at regional, State, and local scales throughout the transportation community.

Format: This product is distributed in shapefile format. The shapefile is an open format created by the Environmental Systems Research Institute (ESRI). You can find additional information about the format at: www.esri.com/library/whitepapers/pdfs/shapefile.pdf

Design: The NTAD2012 databases are designed for use within a geographic information system (GIS); however, the attribute data for each dataset can be accessed in any database, spreadsheet, or other software package. This information is stored in dBASE format. Because of spreadsheet limitations, many of the larger dBASE files will not open correctly with spreadsheet software. It is important to note that users who manipulate attribute data outside of their GIS may alter the shapfiles’ linkage between the attribute and spatial data.

Compilation: The data used to compile NTAD2012 was provided by our partners within the U.S. Department of Transportation (USDOT) and by other Federal Government agencies. These contributors are the data stewards and are ultimately responsible for the maintenance and accuracy of the data. BTS performs structured quality evaluations on these data before they are included in the NTAD. Further details pertaining to the NTAD2012 compilation process may be found in the metadata file associated with each dataset.

Contents

NTAD2012 is organized into subdirectories, one for each feature type (point, polyline, and polygon) and one for each database. At the top level of the DVD, there is also a doc’s subdirectory containing the back cover notes and these liner notes. Also at the top level of the DVD there is a pdf version of the BTS 2012 map of Major Transportation Facilities of the United States. This map showcases many of the data contained in NTAD2012.

Transportation networks are polyline databases. Transportation facilities are point databases. The geographic reference databases may exist as any of the three feature types: point, polyline, or polygon.

All data included here are in shapefile format. Each shapefile dataset within NTAD2012 in general is composed of eight different files:

1. main file (.shp) – feature geometry;
2. index file (.shx) – indices of the feature geometry;
3. dBASE file (.dbf) – attribute information for the features;
4. projection file (.prj) – projection and datum information for the dataset;
5. spatial index file (.sbx) – spatial index for read-write of shapefiles;
6. spatial index file (.sbn) – spatial index for read-write of shapefiles.
7. metadata file (.xml) – xml encoding of shapefile’s metadata; and
8. metadata file (.txt) – text version of shapefile’s metadata – FGDC format.

The shapefile format is a simple, nontopological format for storing the geographic location and attribute information of spatial features. For further information concerning the definition of SHAPE, consult ESRI documentation.

A listing of the NTAD2012 database subdirectories, with a brief description of each, follows. Please refer to the metadata for more detailed descriptions of each dataset.

Point

airports *updated* Airports—Landing facilities in the United States—Data provided and maintained by the Federal Aviation Administration, 2012.

altfuels Alternative Fuels—A geographic point database of fueling facilities that offer fuels other than gasoline in the United States. The data was compiled by BTS, 2008.

amtrk_sta Amtrak Stations—Data provided and maintained by the Federal Railroad Administration, 2010.

atr Automatic Traffic Recorder Stations—Data on stations where highway vehicle counts are recorded. The data is provided and maintained by State Departments of Transportation and submitted to the Federal Highway Administration, 2006.

border_x *updated* Border Crossing Ports are points of entry for land modes along the U.S. - Canadian and U.S. - Mexican borders. This data is created and maintained by the Customs and Border Protection, and spatially enhanced by BTS, 2012. 

facility Intermodal Terminal Facilities—Data on locations where freight can be transferred between modes of transportation. This data has been compiled by the Bureau of Transportation Statistics, 2003.

nbi *updated* National Bridge Inventory—A database containing information on the more than 600,000 bridges located on public roads, including Interstate highways, U.S. highways, State and county roads, as well as publicly accessible bridges on Federal lands. Data provided by the individual State DOTs to the Federal Highway Administration, 2012.

place National Populated Places—Place locations from the 2000 Census Master Area Reference File–Data provided and maintained by the Bureau of the Census, 2000, with additional attribute information from the Geographic Names Information System 2003.

ports *updated* U.S. Army Corps of Engineers Ports—Data provided and maintained by the USACE, 2012.

rr_bridges Railroad Bridges – Dataset railroad bridges over the navigable and non-navigable waterways for the contiguous United States. Data provided and maintained by the Federal Railroad Administration, 2010.

rr_crossings *updated* Railroad Grade Crossings—Data on use and physical characteristics of highway-rail crossings. Data provided and maintained by the Federal Railroad Administration, 2012.

wim Weigh in Motion Stations—Data on stations where highway vehicle weight is recorded. The data is provided and maintained by State Departments of Transportation and submitted to the Federal Highway Administration, 2006.

Polygon

boc_uza Bureau of the Census Urbanized Area Boundaries—Data provided and maintained by the Bureau of theCensus, 2000.

cbsa *updated* Core Based Statistical Areas—Metropolitan and micropolitan statistical areas (referred to generically as "core based statistical areas" or CBSAs) are statistical geographic areas defined by the Federal Office of Management and Budget and maintained by the Bureau of the Census, 2012.

cd112 The 112th Congressional Districts Boundaries—Data provided and maintained by the Bureau of the Census, 2009.

county *updated* U.S. County Boundaries—Data provided and maintained by the Bureau of the Census, 2010. Data was derived by clipping the county_pol shapefile (using the 2000 state shapefile) to cut in the shorelines.

county_pol *updated* U.S. County Boundaries representing the U.S. political boundaries—Data provided and maintained by the Bureau of the Census, 2010. This dataset is contained in the county directory.

hydro Hydrographic Features—Data provided and maintained by the BTS, 2006. (Note: A linear shapefile called “hydrolin” is also provided.)

milbase U.S. Military Installations—Data provided by the Military Surface Deployment and Distribution Command - Transportation Engineering Agency, 2012.

mpo *updated* Metropolitan Planning Organization—Database of MPO planning area boundaries collected by BTS and FHWA, 2012.

naa Non Attainment Areas—Environmental Protection Agency (EPA)-defined areas of the country where “air pollution levels persistently exceed the new national ambient air quality standards,” 2006.

parks *updated* National Park System Boundary Dataset—Data provided and maintained by the National Park Service, 2012.

state *updated* U.S. State Boundaries—Data provided and maintained by the Bureau of the Census, 2010. Data was derived by clipping the state_pol shapefile (using the 2000 state shapefile) to cut in the shorelines.

state_pol *updated* U.S. State Boundaries representing the U.S. political boundaries—Data provided and maintained by the Bureau of the Census, 2010. Data was derived by partially extracting (dissolving) the county_pol shapefile. This dataset is contained in the state directory.

Polyline

faf3 Freight Analysis Framework—Integrates data from a variety of sources to estimate commodity flows and related freight transportation activity among states, regions, and major international gateways. The FAF is maintainted by the Federal Highway Administration.

hazmat Hazardous Material Routes—Data on highway routes for hazardous materials. The data is provided and maintained by the Federal Motor Carrier Safety Administration, 2006.

hpms Highway Performance Monitoring System—Data provided and maintained by State Departments of Transportation and submitted to the Federal Highway Administration, 2010. Attributes represent calendar year 2008. Because of the size of the attribute file, the HPMS data is distribute in ZIP format. Be aware that the unzipped HPMS data is more than 400 MB.

nhpn *updated* National Highway Planning Network—Spatial network of principal roadways within the United States. Data provided and maintained by the Federal Highway Administration, 2012. (Note: A nodal shapefile called “nhpnnd” is also provided.)

rail *updated* Railway Network—Spatial network of rail lines within the United States. Data provided and maintained by the Federal Railroad Administration, 2012. (Note: A nodal shapefile called “railwaynd” and AMTRAK lines are also provided.)

runway *updated* Airport Runways—Spatial data on airport runways within the United States. Data provided and maintained by the Federal Aviation Administration, 2012.

transit Fixed-Guideway Transit Facilities—Transit database including fixed guideway links and stations, 2004.

waterway *updated* U.S. Army Corps of Engineers Navigable Waterway Network—Data provided and maintained by the USACE, 2012. (Note: A nodal shapefile called “waterwaynd” is also provided.)

Technical Support

For assistance using this DVD or the data it contains, please contact BTS at 800-853-1351 or 202-366-3492 and refer to the NTAD2012. Inquiries may also be sent via e-mail.

For assistance with importing the data into a GIS software package, please contact technical support for the specific GIS software vendor.

User comments are critical to improving future editions of NTAD. Your feedback and corrections will be incorporated into the subsequent releases of these datasets. Please check our website (http://www.bts.gov/programs/geographic_information_services/) for any corrections or addendums to NTAD2012.

Acknowledgments

NTAD2012 is the result of cooperation throughout the U.S. Department of Transportation, the U.S. Army Corps of Engineers, the U.S. Bureau of the Census, the Environmental Protection Agency, the Military Surface Deployment and Distribution Command - Transportation Engineering Agency, and the National Park Service.

Most of the geographic reference datasets are products derived from the TIGER database, the TIGER /Line files, or other products created and maintained by the U.S. Bureau of the Census. We greatly appreciate these contributions.

Special thanks are given to the following individuals and organizations which contributed the data that made NTAD2012 possible: Steven Morris of the Military Surface Deployment and Distribution Command - Transportation Engineering Agency; Raquel Hunt of the Federal Railroad Administration; and the Federal Aviation Administration’s Aeronautical Information Services Office. We would also like to recognize the contributions of the following individuals within the Research and Innovative Technology Administration’s Bureau of Transportation Statistics who were responsible for compiling NTAD2012:  Stephen Lewis, Derald Dudley, Jacob Hommeland, Yaguang Xu, Dominic Menegus, and Mark Bradford.