A person is sitting on a rock ledge overlooking a body of water.
One individual is watching looking at how far it is down to the water.
Just because the person is sitting on a rock ledge overlooking a body of water does not tell what they are looking at.  There is nothing to imply that the person is looking at how far it is down.  They could be looking at the sky or the horizon or anything else.
exists e2 e1 x1 x2 x3 x4 x5 x6.(on(e1,x2) & Theme(e2,x5) & Actor(e2,x4) & v_overlook(e2) & of(x5,x6) & n_water(x6) & n_body(x5) & (x2 = x4) & n_ledge(x2) & of(x2,x3) & n_rock(x3) & Actor(e1,x1) & v_sit(e1) & n_person(x1))
exists e2 e1 s1 x1 x2 x3.(n_water(x3) & r_how(s1) & r_far(s1) & to(s1,x3) & Theme(s1,x1) & a_down(s1) & n_thing(x1) & for(e1,e2) & Actor(e2,x1) & v_watch(e2) & at(e1,x2) & n_thing(x2) & Actor(e1,x1) & v_look(e1) & n_individual(x1) & card_eq_1(x1))