Dozens of two-dimentional aerial photo calibration targets are scattered all across the United States, according to a report by the Center for Land Use Interpretation. Constructed mostly during the 1950s and 1960s, these large outdoor charts were used as ‘a platform to test, calibrate, and focus aerial cameras traveling at different speeds and altitudes.’ The report points out that although some of these ‘charts’ are still used for some optical camera testing and calibration, they are primarily relics of the past. Click through for more information, and images.
News: Digital Photography Review (dpreview.com)