Virtual course: Control #9

This control illustrates the principle of secondary viewing points. The left hand photograph, taken from the decision point, shows that all the flags are set in the long ditch. It is not possible to see the short ditch.

In this case it is essential to find another sighting position from which the second ditch can be seen. This sighting position is known as a secondary viewing point. The path to the south of the control is not prohibited (there is no bar marked over the path on the map). So it is possible to move along this path and sight along the short ditch to confirm that one of the flags is indeed on the junction.

If visibility permits, the competitor keeps a continuous eye on the flag while returning to the decision point. If this is not possible, any distinctive features in the terrain next to the flag are noted as markers. This second method can be carried out in the photographs to identify Flag C.

Solution: Flag C

Advanced tip

Look out for parallax errors! When moving from a secondary viewing position to the decision point, the left to right order of the flags may change. In the example above the most distant flag is Flag B when viewed from the decision point but would be labelled Flag A from the secondary viewing point. In this case Flag C is the same from both positions.