National Transportation Atlas Databases: 2001

The National Transportation Atlas Databases-2001 (NTAD-2001) is a set of national geographic databases of transportation facilities. These databases include geospatial information for transportation modal networks and intermodal terminals and related attribute information. Included are descriptions of the file formats and database metadata as prescribed by the Federal Geographic Data Committee. The data on this compact disc (CD-ROM) support research, analysis, and decision-making across all modes of transportation. The databases are most useful at the national level, but have major applications at regional, state, and local scale throughout the transportation community.

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

The NTAD2001 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 shapefiles' linkage between the attribute and spatial data.