Other satellites do not remain suspended above a fixed point
on Earth. The plane of their orbit forms an angle with the
plane of the equator. They can move in a polar (over the poles),
direct (inclination between 0 and 90°, whereby they move
eastward) or retrograde (inclination between 90° and 180°,
westward movement) orbit.
SPOT, for example is a polar satellite. A single revolution
of SPOT takes 101 minutes, thus 101 minutes later it once
again crosses the same degree of latitude. In the meantime,
however, the earth has revolved further to the east. Thus
it takes several days before it will once again fly over the
same place. With SPOT, this period is 370 revolutions x 101
minutes = 26 days. Moreover, each time they fly over the same
area at around the same hour: for example, SPOT always flies
over Belgium at about 11 a.m. In this way, one can monitor
seasonal variations at regular intervals.