Compass Points
The compass rose is an old design element found on compasses, maps and even monuments (e.g. the Tower of the Winds in Athens, the pavement in Dougga, Tunis, during Roman times) to show cardinal directions and frequently intermediate direction. The "rose" term arises from the fairly ornate figures used with early compasses. Older sources sometimes use the term "compass star", or stella maris ("star of the sea"), to refer to the compass rose.
Early forms of the compass rose were known as wind roses, since no differentiation was made between a directional point and the wind which emanated from that direction. (Today, the term "wind rose" is often reserved for the object used by meteorologists to depict wind frequencies from different directions at a location.)
The modern compass rose has eight principal winds. Listed clockwise, these are:
| Compass Point | Abbr. | Direction | Traditional Wind |
|---|---|---|---|
| North | N | 0° | Tramontane |
| North-East | NE | 45° (45° × 1) | Greco or Gregale |
| East | E | 90° (45° × 2) | Levante |
| South-East | SE | 135° (45° × 3) | Scirocco |
| South | S | 180° (45° × 4) | Ostro or Mezzogiorno |
| South-West | SW | 225° (45° × 5) | Libeccio or Garbino |
| West | W | 270° (45° × 6) | Ponente |
| North-West | NW | 315° (45° × 7) | Maestro or Mistral |
Although modern compasses uses the names of the eight principal directions (N, NE, E, SE, etc.), older compasses use the traditional Italianate wind names of Medieval origin (Tramontana, Greco, Levante, etc.)
4-point compass roses use only the four "basic winds" or "cardinal directions" (North, East, South, West), with angles of difference at 90°.
8-point compass roses us the eight principal winds—that is, the four cardinal directions (N, E, S, W) plus the four "intercardinal" or "ordinal directions" (NE, SE, SW, NW), at angles of difference of 45°.
16-point compass roses are constructed by bisecting the angles of the principal winds to come up with intermediate compass points, known as half-winds, at angles of difference of 221⁄2°. The names of the half-winds are simply combinations of the principal winds to either side, e.g. North-northeast (NNE), East-northeast (ENE), etc.
32-point compass roses are constructed by bisecting these angles, and coming up with quarter-winds at 111⁄4° angles of difference. Quarter-wind names are constructed with the names "X by Y", which can be read as "one quarter wind from X toward Y", e.g. North-by-east (NbE) is one quarter wind from North towards East, Northeast-by-north (NEbN) is one quarter wind from Northeast toward North. Naming all 32 points on the rose is called "boxing the compass".
The 32-point rose has the uncomfortable number of 111⁄4° between points, but is easily found by halving divisions and may have been easier for those not using a 360° circle. Using gradians, of which there are 400 in a circle, the sixteen-point rose will have twenty-five gradians per point.
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A 4-point compass rose
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An 8-point compass rose
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A 16-point compass rose
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A 32-point compass rose
Read more about this topic: Compass Rose
Famous quotes containing the words compass and/or points:
“It is not for man to follow the trail of truth too far, since by so doing he entirely loses the directing compass of his mind.”
—Herman Melville (1819–1891)
“Mankind is not a circle with a single center but an ellipse with two focal points of which facts are one and ideas the other.”
—Victor Hugo (1802–1885)