USGS EROS Archive - Aerial Photography - National Aerial Photography Program (NAPP)
Science Center Objects
More than 1.3 million cloud-free black-and-white and color infrared aerial photographs over the United States were obtained from an altitude of 20,000 feet.
The National Aerial Photography Program (NAPP) was coordinated by the USGS as an interagency project to acquire cloud-free aerial photographs at an altitude of 20,000 feet above mean terrain elevation. The photographs were taken with a 6-inch focal length lens at a scale of 1:40,000. Coverage over the conterminous United States includes both black-and-white (BW) and color infrared (CIR) aerial photographs. Film type and extent of coverage were determined by available funds and operational requirements.
The NAPP program, which was operational from 1987 to 2007, consists of more than 1.3 million images. Photographs were acquired on 9-inch film and were centered over quarters of USGS 7.5-minute quadrangles.
The NAPP collection includes black-and-white and color infrared images.
Black-and-white (BW) panchromatic film is sensitive to the full visible portion of the electromagnetic spectrum of light and captures images in tones of gray ranging from black to white.
Color infrared (CIR), or false color, film is sensitive to green and red in the visible portion of spectrum of light and extends into the near-infrared region of the spectrum. Vegetation is distinctly red to magenta in CIR images because vegetation is highly reflective in the near-infrared portion of the spectrum. CIR photography uses high-speed film that is subject to degradation prior to processing, which can create an overall blue cast to the image.
The scale of the image is the ratio of the distance on the image compared to the equivalent distance on the ground. An image with a scale of 1:40,000 means that one inch on the photo is equivalent to 40,000 inches on the ground. A 9 x 9-inch image with a scale of 1:40,000 (1 inch equals about 0.6 miles) covers an area of approximately 5.5 x 5.5 miles on the ground.
Aerial photographs are acquired by aircraft equipped with mapping cameras. The recording technique for the NAPP film collection is vertical photography, which is obtained with the camera pointed directly at the ground.
Flight lines for the NAPP program were flown in a north-to-south direction through the east and west halves of 7.5-minute quadrangles, also known as 1:24,000-scale topographic maps. Images are cartographic quality with a 60% overlap of images to allow for stereographic viewing with specialized equipment.
Commercial flight contractors were required to meet a stringent list of acceptance criteria in order to fulfill contract requirements. All photographs were manually assessed to ensure that they met the photographic, cartographic, coverage accuracy, and quality standards of the NAPP program.
Even though the images in the NAPP collection met contract requirements, users should note that the images have not been geocorrected. The images may have feature displacement and scale variation caused by differences in elevation, lens distortion, and camera tilt. Since the medium and high resolution digital products are reproductions of aerial photographs, any geometric inaccuracies in the original photograph are carried over into the digital products.
EarthExplorer offers the entire NAPP collection, which includes accepted photography as well as any other frames on the roll of film. To view additional frames on a roll of film in EarthExplorer, set up a search for your area of interest then select the “View Entire Roll” () icon by one of the images on the results page. Images have been captured as they appear on the roll of film and may need to be rotated to adjust the orientation.
USGS EROS offers medium and high resolution digital products for the NAPP collection. Products are stored in Tagged Image File Format (TIFF).
The medium resolution digital NAPP products were created with a digital single-lens reflex camera at a resolution of 63 microns, or 400 dots per inch (dpi). These products can be downloaded through EarthExplorer.
The USGS Film Archive is being systematically scanned with digital scanning back systems at a resolution of 25 microns beginning with film sources that are affected by vinegar syndrome degradation. High resolution scans of NAPP photography will be offered to the public at no charge after the work has been completed for older photography. USGS EROS is currently offering on-demand scanning services for NAPP photography to meet customer requirements for high resolution scanned images.
On-demand scanning is available for NAPP film sources that are held in the USGS EROS film archive. EarthExplorer has an “Order Scene” icon () on the results page for images that are available for photogrammetric quality scanning. Options for high resolution BW images include 25 microns (1,000 dpi), 14 microns (1,800 dpi), or 7 microns (3,600 dpi). Options for high resolution CIR images include 25 microns (1,000 dpi) or 14 microns (1,800 dpi). Color images are limited to 14 micron due to file size. On-demand film scans are not archived in the USGS EROS database and are not available for download through EarthExplorer.
|Product Type||Micron Size||BW File Size||Color File Size|
|Medium Resolution Download||63 Micron||15 MB||45 MB|
|High Resolution Download||25 Micron||120 MB||360 MB|
|On-Demand Film Scan||25 Micron||120 MB||360 MB|
|On-Demand Film Scan||14 Micron||260 MB||780 MB|
|On-Demand Film Scan||7 Micron||1 GB||Not available|
Medium resolution and existing high resolution NAPP images at 25 microns are available for download at no cost.
On-demand higher resolution film scans are available for $30.00 per frame (14 micron for color frames and 7 to14micron for back and white frames). A $5.00 handling fee is charged for each on-demand scanning order.
Coverage Maps indicating the availability of NAPP products are available for download.
- Camera Calibrations
- Understanding Color-Infrared Photographs Fact Sheet
- Aerial FAQs
- National Aerial Photography Program (NAPP) Digital Object Identifier (DOI) number: /10.5066/F7VD6WQZ
EarthExplorer can be used to search, preview, and download medium resolution digital files at no cost. Existing high resolution images at 25 microns are also available for download at no cost.
For all other higher resolution imagery, an order will need to be placed in EarthExplorer to scan the film at $30.00 per frame. The collection is located under the Aerial Imagery category as NAPP.
In addition, aerial photographic reproductions and digital products for the NAPP collection can be ordered through the USDA Aerial Photography Field Office (APFO)