TIGER/Line Shapefile, 2012, Series Information File for the Current Other Identifiers Relationship Files

The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the
U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) Database (MTDB). The MTDB represents
a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data
set, or they can be combined to cover the entire nation. The Other Identifiers Relationship File contains external identifier codes, such as National
Hydrographic Dataset (NHD) codes and individual county identifiers. The edge to which an Other Identifiers Relationship File record applies can be
determined by linking to the All Lines shapefile on the permanent edge identifier (TLID) attribute. Not every TLID has an external identifier associated
with it and some TLIDs may have more than one.