Aug 2, 2010
Atlas of Historical County Boundaries
“Presents in maps and text complete data about the creation and all subsequent changes (dated to the day) in the size, shape, and location of every county…
“Presents in maps and text complete data about the creation and all subsequent changes (dated to the day) in the size, shape, and location of every county…
A center within Columbia University’s Earth Institute, CIESIN provides an extensive gateway to data and other information focusing on human interactions…
From the EPA, map various types of environmental information, including air releases, drinking water, toxic releases, hazardous wastes, water discharge…