This dataset is a polyline coverage representing the Bailey Equal-Area Grid. The Bailey Equal-Area Grid is an area-reference grid that uses meridians and parallels to divide the earth's surface into cells of equal area. The grid can be used for comparing area in any map projection. An earlier version of this dataset appears in ESRI's ArcWorld Supplement (1996). This version of the dataset was published as part of the USGS Global GIS : global coverage database (2003). The Bailey Equal-Area Grid data set was mathematically generated by ESRI according to the methodology described in the article, 'A Grid Formed of Meridians and Parallels for the Comparison and Measurement of Area' by Dr. Harry P. Bailey. The USGS Global GIS database contains a wealth of USGS and other public domain data, including global coverages of elevation, landcover, seismicity, and resources of minerals and energy at a nominal scale of 1:1 million. The U.S. Geological Survey (USGS) and The American Geological Institute (AGI) announced a cooperative agreement that will focus on making the USGS Global Geographic Information System (GIS) database readily available to educators and the general public in the form of a DVD based world atlas.