Zenith
North
Figurę 1; The 7 eiements of the geomagnetic field vector S„ associated with an arbitrary point in space
The quantities X, Y, and Z are the sizes of perpendicular vectors that add vectorialiy to Bm. Conversely, X, Y, and Z can be determined from the quantities F, I, and D (i.e., the quantities that specify the size and direction of Bm).
3