A wealth of geospatial data has been developed over the last 30 years, and the discovery and access to that data is still evolving, including our understanding of which data is spatial, which data is authoritative and which is available for unfettered access.
PA Spatial Data Access (PASDA)
The richest catalog of spatial data is found at the official clearinghouse at Pennsylvania Spatial Data Access (psu.edu). This is the source for data more typically associated with GIS, and is documented with FGDC-compliant metadata that makes it suitable for analytical tasks as well as basic display and cartographic uses.
PA Open Data Portal
Much additional information is found at the state’s official Open Data Portal. The site is developing applications that inform simply and the site exemplifies the transparency of operations today.
PA State Data Center
A rich source of demographic data is found at the Pennsylvania State Data Center, partner to the U.S. Census Bureau here in the Commonwealth. It provides data, services, and visualizations based on Census geographies.
Counties produce and maintain important data, and especially site addresses and land ownership information. Each of the 67 counties is autonomous, and data access is variable; some have their own Open Data sites, most have some type of web access or viewer, and many post data for download on PASDA.