A polygon dataset of current ports in the SNK REA - derived from the Tiger/Line File (see the process steps for details). (The TIGER/Line Files are shapefiles and related database files (.dbf) that 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 File is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. The TIGER/Line Files include both incorporated places (legal entities) and census designated places or CDPs (statistical [...]