South-Central Pennsylvania imagery from PA Geological Survey/USGS Orthoimagery for south-central Pennsylvania captured in April of 2003. These images are MrSid compressed natural color orthoimages which were produced at 2-feet pixel resolution. Each tile represents a portion of a ten county area located in south-central Pennsylvania.
Numerous downloadable data for Philadelphia. See also the web interface at http://citymaps.phila.gov/citymaps/default.aspx
Follow this link to the The Penn State University Libraries Maps and Data Center download site
What’s In My Watershed? is a mapping application that provides the user with an easy to use tool for locating their neighborhood and obtaining information about their environment.
Pennsylvania resource for GIS data downloads – Pennsylvania Spatial Data Access (PASDA) is Pennsylvania’s official public access geospatial information clearinghouse.