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| USGS › Geography › Earth Resources Observation and Science (EROS) Center |
Photo index (Southwestern Pennsylvania)
Individual aerial photograph from photo index (Southwestern Pennsylvania)
Photo Reference Mosaics were mainly produced during the creation and refining of the U.S. Geological Survey (USGS) topographic map series. The film is referenced as a series of photo indexes (mosaics), each of which consists of a single-sheet composite of many individual photos. The photos date from the 1940s to 1980s, and they were originally acquired by a variety of sources, such as the USGS, Environmental Protection Agency, Bureau of Land Management, U.S. Air Force, and U.S. Navy.
Index/Mapping Photography is not a standardized product, and individual photos will vary in scale, size, quality, and coverage. Almost all of the photos were taken from a vertical perspective. Most are in black & white (B/W), although color and color-infrared (CIR) may be available for some locations.
The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center is digitizing all photo indexes in the archive and the individual frames from each index. The current plan is to begin creating browse images from USGS indexes and USGS historical photographs, followed by other agency collections.
Currently, the majority of the USGS mosaics are available to view and download as a full-resolution jpeg. These can be searched on EarthExplorer in the Aerial Photographs - USGS Photo Reference Mosaic collection. To order a High Resolution Scanned product only, select the frame of interest and contact USGS Customer Services.
As soon as an entire Project has been digitized, the individual frames will be available to search and order on EarthExplorer. These frames are available as a High Resolution Scanned or Medium Resolution Digitized product. A status map is available showing where individual frames from Indexes are available. At this time, only 9 by 9-inch source photographs will be available as a digitized product. Contact USGS Customer Services for more information.
Businesses that can provide printed images from USGS digital data.
| Film Size | Micron Size | Black and white (B/W) | Color-infrared (CIR) |
|---|---|---|---|
| 9 x 9 in | 21 Micron | 117 MB | 350 MB |
| 14 Micron | 262 MB | 787 MB | |
| 7 Micron | 1.3 GB | Not Available* | |
| 9 x 9 in | 21 Micron | 117 MB (x 2 files) | 350 MB (x 2 files) |
| 14 Micron | 262 MB (x 2 files) | 787 MB (x 2 files) | |
| 7 Micron | 1.3 GB (x 2 files) | Not Available* |
* Color/CIR film source is not available at a 7- micron spot size because the file size is too large and there are no advantages below the 14-micron spot size.
The above sizes may vary due to scanning more than just image data. The files are created in TIFF format. With our procedure of scanning the surrounding metadata and adding the USGS logo, the actual image size will generally be larger than the estimates above.
The file sizes are about 15 megabytes for black and white images and 40 megabytes for color images. The files are stored in a TIFF format. The medium-resolution files are created at about 400 dpi.
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