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True North(band)
True north (also called geodetic north or geographic north) is the Cardinal direction, direction along Earth's surface towards the geographic North Pole or True North Pole. geodesy, Geodetic north differs from ''magnetic'' north (the direction a points of the compass, compass points toward the Magnetic North Pole), and from grid north (the direction northwards along the grid lines of a map projection). Geodetic true north also differs very slightly from ''astronomical'' true north (typically by a few arcseconds) because the local gravity, gravitational field may not point at the exact axis of rotation, rotational axis of Earth. The direction of astronomical true north is marked in the skies by the north celestial pole. This is within about 1° of the position of Polaris, meaning pole star, the star would appear to star trail, trace a tiny circle in the sky each sidereal time, sidereal day. Due to the axial precession of Earth, true north rotates in an arc with respect to fixed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardinal Direction
The four cardinal directions, or cardinal points, are the four main compass directions: north, east, south, and west, commonly denoted by their initials N, E, S, and W respectively. Relative to north, the directions east, south, and west are at 90 degree intervals in the clockwise direction. The ordinal directions (also called the intercardinal directions) are northeast (NE), southeast (SE), southwest (SW), and northwest (NW). The intermediate direction of every set of intercardinal and cardinal direction is called a secondary intercardinal direction. These eight shortest points in the compass rose shown to the right are: # West-northwest (WNW) # North-northwest (NNW) # North-northeast (NNE) # East-northeast (ENE) # East-southeast (ESE) # South-southeast (SSE) # South-southwest (SSW) # West-southwest (WSW) Points between the cardinal directions form the points of the compass. Arbitrary horizontal directions may be indicated by their azimuth angle value. Determination Addi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
