The
Greater Philadelphia GeoHistory Network is an application that provides access to historic geographic resources including maps, atlases, surveys, and directories. A pilot project of the Philadelphia Area Consortium of Special Collections Libraries (PACSCL) and expanded by the Athenaeum of Philadelphia, the site contains items from a number of contributors and organizations. The Interactive Map Viewer feature enables users to layer historic maps, aerial photography, and a current street plan to gain a new understanding of Philadelphia.