The United States’ largest water, earth, and biological science and civilian mapping agency, the U.S. Geological Survey (USGS), was organized in 1879 and recently celebrated the 125th anniversary of its national program for topographic maps (1884-2009). More than 55,000 7.5-minute, 1:24,000-scale topographic maps were compiled and published by USGS in the twentieth century, culminating in complete coverage of the contiguous 48 states in 1991. To celebrate, ESRI has just released this awesome PDF document titled “125 Years of Topographic Mapping at USGS” – enjoy! Download HERE
