The USGS TopoView enhancement, TopoView 2.1, brings historical topo maps to your fingertips in the popular open-source mapping platform. Users can compare historical maps with modern day maps to see how the landforms and regional names have changed over time. In addition to accessing the historical maps, additional upgrades to previous versions were made based on user feedback.
The USGS published an update to the State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. It represents a seamless, spatial database of 48 State geologic maps that range from 1:50,000 to 1:1,000,000 scale, and this version includes updated data for six states, data for seven entirely new states, and numerous corrected errors since the preliminary dataset was launched.