When the contact is on the opposite course to own ship, on the same course as own ship or is a stationary contact, the Relative Motion Line will run parallel to own ship's course line. Own ship's true course vector, in these cases, will fall on top of the Relative Motion Line and the plot will be a straight line.
Regardless of the shape of the plot, the same plotting procedures must still be followed. Calculate own ship's distance run to determine the current location of point (e).
A. If point (e) falls on top of point (m), the contact is stationary (it has no course or speed).
B. If point (e) falls beyond points (r) and (m), the contact is on the same course as own ship.
C. If point (e) falls between the contact's first position (r) and the last position (m), the contact is on the opposite course to own ship.
D. If point (r) and point (m) fall on top of one another, the contact has the same course and speed as own ship.
