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The points of the compass are points on a compass, specifically on the compass rose, marking divisions of the four cardinal directions: North, South, East, West. The number of points may be only the 4 cardinal points, or the 8 principal points adding the intercardinal (or ordinal) directions northeast (NE), southeast (SE), southwest (SW), and northwest (NW). In meteorological usage further intermediate points are added to give the sixteen points of a wind compass.〔David Boardman Graphicacy and Geography Teaching 1983 – Page 41 "In particular they should learn that wind direction is always stated as the direction from which, and not to which, the wind is blowing. Once children have grasped these eight points they can learn the full sixteen points of the compass."〕 Finally, at the most complete in European tradition, are found the full thirty-two points of the mariner's compass.〔''Pamphlets on British shipping. 1785–1861'' 1785– Page 50 "A deviation table having been formed by any of the processes now.so generally understood, either on the thirty-two points of the compass, the sixteen intermediate, or the eight principal points"〕 In ancient China 24 points of the compass were used. In the mariner's exercise of boxing the compass, all thirty-two points of the compass are named in clockwise order.〔George Payn Quackenbos A Natural Philosophy: Embracing the Most Recent Discoveries 1860 "Mentioning the mariner's compass: the points of the compass in their order is called boxing the compass. — The compass box is suspended within a larger box by means of two brass hoops, or gimbals as they are called, supported at opposite ..."〕 The names of intermediate points are formed by the initials of the cardinal directions and their intermediate ordinal directions, and are very handy to refer to a heading (or course or azimuth) in a general or colloquial fashion, without having to resort to computing or recalling degrees. For most applications, the minor points have been superseded by degrees measured clockwise from North. == Compass point names == The names of the 32-wind compass rose follow these rules: * The cardinal directions are North (N), East (E), South (S), West (W), at 90° angles on the compass rose. * The ordinal (or intercardinal) directions are Northeast (NE), Southeast (SE), Southwest (SW) and Northwest (NW), formed by bisecting the angle of the cardinal winds. The name is merely a combination of the cardinals it bisects. * The eight principal winds (or main winds) are the cardinals and ordinals considered together, that is N, NE, E, SE, S, SW, W, NW. Each principal wind is 45° from its neighbour. The principal winds form the basic eight-wind compass rose. * The eight half-winds are the points obtained by bisecting the angles between the principal winds. The half-winds are North-northeast (NNE), East-northeast (ENE), East-southeast (ESE), South-southeast (SSE), South-southwest (SSW), West-southwest (WSW), West-northwest (WNW) and North-northwest (NNW). Notice that the name is constructed simply by combining the names of the principal winds to either side, with the cardinal wind coming first, the ordinal wind second. The eight principal winds and the eight half-winds together yield a 16-wind compass rose, with each compass point at a ° angle from the next. * The sixteen quarter winds are the direction points obtained by bisecting the angles between the points on a 16-wind compass rose. The sixteen quarter-winds are North by east (NbE), Northeast by north (NEbN), Northeast by east (NEbE), East by north (EbN) in the first quadrant, East by south (EbS), Southeast by east (SEbE), Southeast by south (SEbS), South by east (SbE) in the second quadrant, South by west (SbW), Southwest by south (SWbS), Southwest by west (SWbW), West by south (WbS) in the third quadrant, and finally West by north (WbN), Northwest by west (NWbW), Northwest by north (NWbN) and North by west (NbW) in the fourth quadrant.〔(Compass rose at geography.about.com )〕〔(Washington Education )〕 The name of a quarter-wind is typically "X by Y", where X is a principal wind and Y is a cardinal wind. As a mnemonic device, it is useful to think of "X by Y" as a shortcut for the phrase "one quarter wind ''from'' X ''towards'' Y", where a "quarter" is °, X is the nearest principal wind, and Y the next (more distant) cardinal wind. So "Northeast by east" means "one quarter from NE towards E", "Southwest by south" means "one quarter from SW towards S". The eight principal winds, eight half-winds and sixteen quarter winds together yield a 32-wind compass rose, with each compass direction point at ° angle from the next. The title of the Alfred Hitchcock 1959 movie, ''North by Northwest,'' is actually ''not'' a direction point on the 32-wind compass, but the film contains a reference to Northwest Airlines. Similarly, the names of the two film festivals South by Southwest and North by Northeast are not 32-wind compass points; a quarter wind whose name contains both a cardinal and an ordinal direction is named with the ordinal direction first. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Points of the compass」の詳細全文を読む スポンサード リンク
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