What is the term for the center point of an aerial photo where lines through opposing sets of fiducial marks intersect?

The term that refers to the center point of an aerial photo, where lines through opposing sets of fiducial marks intersect, is known as the Principal Point. In aerial photography, fiducial marks are specific reference points located on the edge of a photo that help in the geometric correction and alignment of images. The Principal Point serves as the focal reference for various calculations, including the orientation of the photograph, scale, and photogrammetric measurements. This point is pivotal in ensuring accurate representation and interpretation of the captured images, making it essential in mapping and surveying applications. Other terms such as Orthophoto, Air Base, and Vertical Photographs relate to different concepts in aerial photography and photogrammetry, but do not define the specific location and significance of the intersection if fiducial marks.