Since aerial photographs are seldom exactly the same
scale as a map of the same area, it is not feasible to print
military grids on them. A special grid is used for the
designation of points on photographs (Figure 8-16). This
grid, known as the point designation grid, has no
relation to the scale of the photo, to any direction, or to
the grid used on any other photograph or map. It has
only one purpose, to designate points on photographs.