Exterior orientation defines the position and angular orientation of the camera that captured an image. The variables defining the position and orientation of an image are referred to the as elements of exterior orientation. The elements of exterior orientation define the characteristics associated with an image at the time of exposure or capture. The positional elements of exterior orientation include Xo, Yo, and Zo. They define the position of the perspective centre (o) with respect to the ground space coordinate system (X, Y, and Z). Zo is commonly referred to as height of the camera above sea level, which is commonly defined by a datum. Aerial triangulation was carried out with the aid of the established ground control points as shown in figure 1.6 below.