Points of the compass Points of the compass The points of the compass mark the divisions on a compass, which is primarily divided into the four cardinal directions: north, south, east, and west. These points are further subdivided by the addition of the four intercardinal (or ordinal) directions—northeast (NE), southeast (SE), southwest (SW), and northwest (NW)—to indicate the eight principal winds. In meteorological usage, further intermediate points between the cardinal and intercardinal directions, such as north-northeast (NNE) are added to give the sixteen points of a compass rose. At the most complete division are the full thirty-two points of the mariner's compass, which adds
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