Exploratory Study in Interpretation of Vertical and High Oblique Photographs

Book excerpt: The study set out to determine the relative utility of vertical and oblique views and to define the conditions under which each is more effective. Interpreter performance in extracting information from vertical and oblique views was compared. Sixty-four experienced interpreters, divided into two groups of 32 each, interpreted vertical and oblique views of a common area. Two sets of photographs were used, one of an airfield, the other of a bridge. Performance comparisons for the airfield photos were for common areas constituting the foreground, background, and total area. For the bridge, only the total overlapping area was used. Comparisons were made separately for detection and identification, counting of objects, and mensuration. Vertical photos were found to be better for identification of objects with major dimensions in the horizontal plane, oblique photos for objects with major dimensions in the vertical plane. Mensuration was much easier on vertical photos than on oblique photos. In oblique viewing, completeness of interpretation, but not accuracy, was affected by the portion of the photo being interpreted. For the foreground, completeness was 28.5%, for the background 8.8%. (Author).