Fig. 5
The method of describing and defining different directions from any point, as a center, is clearly explained by this diagram.
DISTANCES
17. The definition of Distances in any direction is well understood. In defining position “B,” in [Fig. 4], we say that it is, in a direction from “A,” the premise-point, down-to-the-right forty-five degrees (45°), that it is at a distance from “A” of one inch. Distances are always taken from premise-points.
POSITIONS DETERMINED
BY TRIANGULATIONS
18. If we mark a third dot, “C,” on our paper and wish to define its position, we may give the direction and the distance from “A,” or from “B,” or, if we prefer, we may follow the principle of Triangulation and give two directions, one from “A” and the other from “B.” No distances need be given in that case. The position of “C” will be found at the intersection of the two directions.
Fig. 6
The principle of Triangulation is illustrated in the above diagram.