Library Aerial Photographs
The Pennsylvania Geological Survey library maintains collections of aerial photographs dating from 1946 to 1999. These collections are from the U.S. Geological Survey and the U.S. Department of Agriculture (see descriptions below). The geographic extents of the collections vary and are indicated on indexes for each series.
Check-out period for aerial photographs is one month. Online appointments should be made for viewing aerial photographs at the library (Middletown office). The list below describes our collection from within each series.
- Agricultural and Stabilization Conservation Series (1946–81). These photographs are leaf on and black and white. The scale is generally 1:20,000, but photographs from the late 1970s and later have scales of 1:40,000. Complete coverage except in Philadelphia. Online aerial photos from 1938-1972 are available through Penn Pilot.
- U.S. Geological Survey (mostly late 1960s and 1970s). The photographs in this series are leaf off and black and white. The scale varies, but in our collection, most photographs are between 1:20,000 and 1:40,000 scale. Complete coverage.
- National High-Altitude Photography (NHAP). This series was initiated in 1980 and was succeeded by the NAPP program. Photographs in this series are high altitude, and most are leaf off and black and white. The scale for black and white photography is 1:80,000. Color-infrared photography is also available at a scale of 1:58,000. Complete coverage.
- National Aerial Photography Program (NAPP). This series was divided into three phases: the first phase started in 1987, the second phase in 1992, and the third phase in 1999. NAPP photographs in our library were acquired in 1987–89, 1992–94, and 1999. In our collection, photographs from 1987–89 are leaf on, most are black and white, and some are color infrared. Prints from the 1990s are leaf off and black and white. NAPP photographs have a scale of 1:40,000. Third phase (1989) is not complete, coverage from part of Central Pennsylvania to Eastern Pennsylvania is complete.
The Pennsylvania Geological Survey had thousands of historical (1937–72) aerial photographs from the Agricultural and Stabilization Conservation Series scanned and put online. These photographs came from our collection and from the State Archives. The images can be located, viewed, and downloaded from Penn Pilot, which is hosted by the Pennsylvania State University, at http://www.pennpilot.psu.edu/. NOTE: not complete
The U.S. Geological Survey offers their aerial photography and other imagery on their Earth Explorer website at http://earthexplorer.usgs.gov/. Some low-resolution images may be downloaded for free. However, users are charged a fee for higher resolution images.
PAMAP – The Digital Base Map of Pennsylvania
PAMAP has acquired high resolution digital orthophotos and elevation data for all of Pennsylvania. Portions of the state were flown each year from 2003 to 2008. The data is primarily of use in Geographic Information System software, where it provides a seamless, consistent, high-resolution set of digital, geospatial data products. A download tool at http://www.pamap.dcnr.state.pa.us/pamap/data_source.aspx provides information and easy access to the files, which can also be downloaded from the PASDA site.
Digital Ortho Quarter Quads (DOQQ)
Digital ortho quarter quads (DOQQ) from 1993 and 1999 for parts of Pennsylvania can be downloaded from PASDA at: ftp://www.pasda.psu.edu/pub/pasda/. There are now two folders that you can download from: doq and doq99. Or visit the PASDA Data Access Wizard and type in “DOQQ” as a key word.
DOQQs are rectified and projected digital aerial photographs covering one quarter of a 7.5 minute quadrangle. A single DOQQ file is typically 40MB in size, so download times over a modem may be unreasonable. The DOQQs at the PASDA site are in the same projection as the most recently published 7.5-minute quadrangle.
The principal file name of each DOQQ is the same as the 7.5 minute quadrangle with the addition of a suffix (NW, NE, SE, SW) indicating which quarter of the quadrangle it covers. Each DOQQ is comprised of two files; the image file, which has BIL as the filename extension; and a header file, which has HDR as the filename extension.