It is obvious that relief displacement is proportional to
the elevation difference Ah. Here, flH is the photo scale.
Small scale photographs are thus less capable of representing
relief displacement information. Objects close to the nadir
point have small distances R and, therefore, will have small
relief displacements. The same elevation difference Ah
would produce a larger relief displacement as the object is
situated farther away from the nadir point. The terms of
Equation (1) are examined for both aerial photography and
satellite image cases (Figure 1) where the object height Ah remains
the same.