This data set was acquired with a ship-based Navigation system during Nathaniel B. Palmer expedition NBP9801 conducted in 1998 (Chief Scientist: Dr. John Anderson). These data files are of SHP format and include Primary Navigation data and were processed after data collection. Data were acquired as part of the project(s): Timing of Retreat of the West Antarctic Ice Sheet, and funding was provided by NSF grant(s): OPP95-27876.