A form of aerial photography in which the axis of the camera is kept as vertical as possible while taking photographs. During a photo run, the photographs are taken continuously and an overlap is provided between the photographs. Similarly, lateral overlap is provided during successive overruns. A composite strip of the area is then made, which is called a mosaic. This is viewed under a stereoscope, which assists in identification of ground features, especially areas that are camouflaged. The scale and the height in a vertical photograph are accurate, which is essential for mapping plan positions. Generally, a forward overlap of 60% and a lateral overlap of 20 to 30% is provided. See vertical air photograph and aerial photography.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved