Points of the compass limit of the compass point. By the middle of the 18th century, the 32-point system had been further extended by using half- and quarter-points to give a total of 128 directions. These fractional points are named by appending, for example east, east, or east to the name of one of the 32 points. Each of the 96 fractional points can be named in two ways, depending on which of the two adjoining whole points is used, for example, NE is equivalent to NbEN. Either form is easily understood but alternative conventions as to correct usage developed in different countries and
Geological compass iPhone using vector algebra. The accelerometers record vibration, so the iPhone needs be held still. Since very many measurements can be made in a few seconds, statistical analysis can be applied. High variance implies scattered data, so measurement should be continued until error diminishes to an acceptable level. It is important to consider such aspects in using a geological compass, for traditional compasses rely on inertia to remove error caused by operator movement. With traditional compasses there is no record of error caused by poor damping or operator movement. This limitation is removed by use of a digital compass, though