The four cardinal directions or cardinal points are north, south, east, and west, commonly denoted by their initials - N, S, E, W. They are mostly used for geographic orientation on Earth but may be calculated anywhere on a rotating astronomical body. North and south point toward the geographical poles defined by the axis of rotation, such that the body appears to rotate counter-clockwise when viewed from above the north pole. East and west are at right angles to north and south, with east being in the direction of rotation and west being directly opposite. Intermediate points between the four cardinal directions form the points of the compass. The intermediate directions are north-east (NE), north-west (NW), south-west (SW), and south-east (SE). On Earth, upright observers facing north will have south behind them, east on their right, and west on their left. Most devices and methods for orientation therefore operate by finding north first, although any other direction is equallyvalid, if it can be reliably located. Several of these devices and methods are described below.