Consider the following equation, and answer the questions that follow:

a)      Name and define the condition related to this equation. (3)

b)      What is the difference between  and ? (3)

c)      What does  refer to? (2)

d) can refer to different points on the image, depending on how it was defined. Name three of these points.  (3)

e)      Name and describe the two primary applications of the collinearity condition used to establish camera–image–ground relationships in photogrammetry.  (6)