Point out a compass direction without the help of a compass.

We abandoned the road and traveled by a footpath across country in the compass direction of our objective.

In contrast, the great circle route provides the shortest distance between the two cities, but the compass direction varies along this route.

This is most easily done by taking the angle at which the strata are inclined and the compass direction in which they slant.

So we took the compass direction, in order to assure consistency at least, and struck off at full right angles to the left.