USA Bailey's Ecoregions polygon map and R script for grid sampling

This package consists of a geo-spatial data file, specifically, an ESRI polygon shape file, containing approximately 1700 polygons depicting the Bailey's Eco Regions classification system. (Consult http://www.nationalatlas.gov/mld/ecoregp.html for a summary of this system). Also included is an R-language script that applies a regularly-spaced point grid on top of the polygon map, and produces a geospatial point file containing samples of the Bailey's region code at each point in the grid