PAMAP—Digital Base Maps for Pennsylvania
The PAMAP Program, which is administered by the Pennsylvania Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey, was a collaborative effort of federal, state, and local government agencies that made possible the collection of a statewide set of high-resolution lidar elevation data and digital orthophotographs. The link Download PAMAP Data will take you to a portal where you can easily select and download PAMAP data products free of charge. The data are stored on servers maintained by Pennsylvania Spatial Data Access (PASDA) and can also be downloaded from the PASDA website (http://www.pasda.psu.edu/).
Data collection for PAMAP began in 2003 and ended in 2008. Digital aerial photography was flown for parts of the state every year during that time period, with some areas being flown twice. As a result of this PAMAP initiative, there is a complete set of 1:2400-scale, leaf-off, full-color orthoimages at a 1-foot pixel resolution available for Pennsylvania. You can visit PAMAP Imagery for more information on this topic.
PAMAP lidar elevation data were collected from 2006 through 2008 with an average point spacing of 1.4 meters and a vertical accuracy of at least 18.5-centimeters RMSE in open areas. The data were processed to produce bare-earth digital elevation models (DEMs) represented by 3.2-foot pixels in GeoTIFF format. In all there are four products available from the PAMAP lidar data: the LAS point clouds, the DEMs, breaklines, and contours. These products are explained more fully on the PAMAP Lidar Elevation Data web page.
For maximum accuracy and compatibility with county GIS programs, PAMAP data were projected into the relevant Pennsylvania North or South State Plane Coordinate System. Each of the two state-plane zones was divided into a grid of tiles (see map on right), which was used to clip the data into systematic files of manageable sizes. The tiles represent areas of 100 million square feet (10,000 feet on each side).