There is no widely accepted standard for analyzing shoreline change. Existing shoreline data measurements and rate calculation methods vary from study to study and prevent combining results into state-wide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method of measuring changes in shoreline position that is consistent from coast to coast. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner.
The UTM coordinate system divides the globe into a grid of nonoverlapping quadrangles, called zones, each 8 by 6 degrees in extent. Each zone uses a transverse version of the Mercator projection.
While it is not typically done, it is possible to extend one zone's coordinates into a neighboring zone's territory. The eastern end of Long Island crosses the boundary between UTM zone 18N and UTM zone 19N. All of the data for Long Island was handled within zone 18N.
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