Especially in color photos, but also in black and white photos, blue and ultraviolet light that is scattered by the atmosphere may degrade the film image. We can reduce this degradation by using a haze filter that absorbs the ultraviolet and the very shortest visible blue wavelengths. Aerial imagery, either individual photos or sections of orthophotoquads, of selected large parts of the United States, has been digitized from data collected by the U.S. Geological Survey. Their resolution ranges from less than 2 to about 12 meters. They market these data worldwide as part of their SPIN-2 program.
All photos are black and white.
Of course, the principles we have been applying in these three pages to aerial photos pertain in many respects to space imagery as well. Mapping once done primarily with air photos can now be done almost as well with space products. The main drawback is resolution, and that limitation is rapidly disappearing with the declassification of high resolution military imagery and with the ever-improving resolution capability of satellites now being flown or on the drawing boards for the foreseeable future.