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| EarthExplorer |
PhotoFinder provides access to two USGS photography collections; National Aerial Photography Program (NAPP) and National High Altitude Photography (NHAP). The following is a brief explanation of each.
NAPP
The National Aerial Photography Program (NAPP) provides a standardized set of cloud-free aerial photographs covering the conterminous U.S. over five-to-seven year cycles. The program began in 1987 and continues to be our most recent and consistent source of high-quality aerial photography.
The photographs were acquired from an altitude of 20,000 feet and are available in black & white (B/W) or color infrared (CIR), depending on location and date. Each photo is centered on one-quarter section of a 7.5-minute USGS quadrangle, and covers approximately a 5.5 x 5.5 mile area.
See the NAPP Products Page, for additional information.
NHAP
The National High Altitude Photography (NHAP) program was in effect from 1980-1989. It was coordinated by the USGS to acquire aerial photography of the 48 conterminous states.
NHAP photography was acquired from an altitude of 40,000 feet. Two different camera systems were used to acquire simultaneous coverage at two different scales. A 6-inch focal length lens acquired black-and-white (B/W) film at an approximate scale of 1:80,000. B/W photos cover a ground area of 11 x 11 miles. An 8.25-inch lens acquired color-infrared (CIR) film at an approximate scale of 1:58,000. CIR photos cover a ground area of 8 x 8 miles.
See the NHAP Product Page, for additional information.
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