GSHHS (Global Self-consistent, Hierarchical, High-resolution Shoreline Database) shoreline data is provided by the NGDC
(National Geophysical Data Center).
GSHHS is a high-resolution shoreline data set amalgamated from two databases in the public domain. The data have
undergone extensive processing and are free of internal inconsistencies such as erratic points and crossing segments. The
shorelines are constructed entirely from hierarchically arranged closed polygons. The data can be used to simplify data
searches and data selections, or to study the statistical characteristics of shorelines and land-masses. It comes with
access software and routines to facilitate decimation based on a standard line-reduction algorithm.