NEW VIEWS OF PENNSYLVANIA'S CULTURAL GEOLOGY AND GEOMORPHOLOGY WITH PAMAP LIDAR

A long history of agricultural, mining and industrial activity has left its mark on the landscape of Pennsylvania. Extensive tree cover has obscured much surface detail from photographic detection. Newly available statewide, consistent, high-resolution lidar data for Pennsylvania allows new perceptions of the land surface of the commonwealth, and suggests new understanding of the development of land features.

Lidar reveals human modifications of the landscape that are ubiquitous and extensive. Identifiable features include roadways, railways, building sites, surface mines and deep mine openings of many ages (reclaimed and not), stream diversions, 18^th century charcoal hearths, canals, legacy sediment accumulations, agricultural regrading, drainage features and stone walls. Lidar also shows previously unrecognized natural geomorphic features, and some structural geology features.

Examination of lidar-derived images indicates that some previously mapped geologic features were misidentified. Aerial photo mapping of landslides missed a number of slides clearly evident with lidar, but also identified some features as landslides which lidar now shows to be erroneous. Lidar reveals karst features in forested areas which were missed in earlier inventories.

The lidar elevation data provides a base layer for comparison with future lidar or other high-resolution elevation data. Change detection, especially related to resource extraction, is a major potential use of the data. PAMAP lidar was collected for approximately one-third of the commonwealth in each of 2006, 2007 and 2008, concurrent with the beginnings of the Marcellus Shale gas well drilling boom.

PAMAP data includes 1-foot resolution Orthophotos, the lidar point cloud (LAS format), a 3.2 foot gridded bare-earth Digital Elevation Model and 2-foot contours. Vertical accuracy is 18.5 cm (7 inches) in open areas, and 37 cm (14 inches) in forested areas. All data can be freely downloaded from the PASDA web site at www.pasda.psu.edu. Information on the program and data is at www.dcnr.state.pa.us/topogeo/pamap. The availability of state-wide data of this resolution, with derivative DEM and contours, is unprecedented, and offers remarkable opportunities to view and model the land and interpret the surface geology and history of Pennsylvania.