Bearings · 方位角
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| bearing/ˈbeərɪŋ/ | 方位角 | fāng wèi jiǎo |
| back bearing/bæk ˈbeərɪŋ/ | 反方位角 | fǎn fāng wèi jiǎo |
Lost at sea — saved by a bearing 方位角
- Before GPS, sailors navigated using bearings — a precise angle from north.
- A single mistake (reading anticlockwise instead of clockwise, or writing "45" instead of "045") could put a ship miles off course.
在海上迷失——被一个方位角拯救
- 在 GPS 之前,水手用方位角(bearings)导航——一个从北方的精确角度。
- 一个错误(逆时针读而不是顺时针,或写"45"而不是"045")能让一艘船偏离航线数英里。
Bearings route · 方位角路线
Follow how to measure a bearing correctly from north. · 演示如何正确从正北方向测量方位角。
What is a bearing?
- A bearing gives a direction as a three-figure angle, measured clockwise from north.
- Due north $= 000^{\circ}$ (or $360^{\circ}$); due east $= 090^{\circ}$; due south $= 180^{\circ}$; due west $= 270^{\circ}$.
- Always write three figures: $5^{\circ}$ becomes $005^{\circ}$, $45^{\circ}$ becomes $045^{\circ}$.
Bearings are always measured clockwise from north, and always written as three figures.
Three figures, always. A bearing of $45^{\circ}$ is written $045^{\circ}$. Writing just "45" loses marks — the leading zero shows it's a bearing, not an ordinary angle.
什么是方位角?
- 一个方位角把一个方向给为一个三位角,从北方顺时针测量。
- 正北 $= 000^{\circ}$(或 $360^{\circ}$);正东 $= 090^{\circ}$;正南 $= 180^{\circ}$;正西 $= 270^{\circ}$。
- 总是写三位数字:$5^{\circ}$ 变成 $005^{\circ}$,$45^{\circ}$ 变成 $045^{\circ}$。
方位角总是从北方顺时针测量,并总是写成三位数字。
三位数字,总是。 一个 $45^{\circ}$ 的方位角写作 $045^{\circ}$。只写"45"会失分——前导零显示它是一个方位角,不是一个普通的角。
What three-figure bearing points due east? · 指向正东方的三位数方位角是多少？
Clockwise from north, east is 090°. · 从正北顺时针旋转，东方是 090°。
Bearings are measured clockwise from north. · 方位角是从正北方向顺时针测量的。
Always clockwise from north, written as three figures. · 始终从正北顺时针测量，并以三位数字表示。
A bearing of 45° should be written as ______°. · 45° 的方位角应写作 ______°。
Bearings are always written as three figures: 045°, not 45°. · 方位角始终以三位数字表示：045°，而不是 45°。
Back bearings 反方位角
- The back bearing (the return direction) differs from the forward bearing by $180^{\circ}$.
- If the bearing is under $180^{\circ}$, add $180^{\circ}$; if over, subtract $180^{\circ}$.
- Bearing of $B$ from $A$ is $025^{\circ}$ → bearing of $A$ from $B$ is $025 + 180 = 205^{\circ}$.
Bearing of $P$ from $Q$ is $310^{\circ}$. Back bearing: $310 - 180 = 130^{\circ}$. The bearing of $Q$ from $P$ is $130^{\circ}$.
Bearings are measured clockwise from north as three figures; the back bearing differs by $180^\circ$
反方位角
- 反方位角(back bearing,返回方向)与前方位角相差 $180^{\circ}$。
- 如果方位角小于 $180^{\circ}$,加 $180^{\circ}$;如果大于,减 $180^{\circ}$。
- $B$ 从 $A$ 的方位角是 $025^{\circ}$ → $A$ 从 $B$ 的方位角是 $025 + 180 = 205^{\circ}$。
$P$ 从 $Q$ 的方位角是 $310^{\circ}$。反方位角:$310 - 180 = 130^{\circ}$。$Q$ 从 $P$ 的方位角是 $130^{\circ}$。
方位角从北方顺时针作为三位数字测量;反方位角相差 $180^\circ$
The bearing of B from A is 025°. What is the bearing of A from B? · B 相对于 A 的方位角是 025°。A 相对于 B 的方位角是多少？
Back bearing: 025 + 180 = 205°. · 反方位角：025 + 180 = 205°。
The bearing of P from Q is 310°. What is the back bearing (bearing of Q from P)? · P 相对于 Q 的方位角是 310°。反方位角（Q 相对于 P 的方位角）是多少？
310° > 180°, so subtract: 310 − 180 = 130°. · 310° > 180°，所以做减法：310 − 180 = 130°。
Worked example — three-figure bearings
- A ship sails on bearing $135^{\circ}$ for $20$ km, then turns to bearing $225^{\circ}$.
- The angle turned through $= 225 - 135 = 90^{\circ}$ — a right-angle turn to starboard.
例题——三位方位角
- 一艘船以方位角 $135^{\circ}$ 航行 $20$ km,然后转到方位角 $225^{\circ}$。
- 转过的角 $= 225 - 135 = 90^{\circ}$——一个向右舷的直角转弯。
A ship changes from bearing 135° to bearing 225°. How many degrees did it turn? · 一艘船从方位角 135° 转向方位角 225°。它转过了多少度？
225 − 135 = 90° (a right-angle turn). · 225 − 135 = 90°（直角转弯）。
Bearings in the real world
- Aviation: runways are numbered by their bearing divided by 10 (Runway 27 faces roughly $270^{\circ}$).
- Hiking: a compass bearing tells you which direction to walk, even in fog.
现实世界中的方位角
- 航空:跑道按它们的方位角除以 10 编号(27 号跑道大致朝向 $270^{\circ}$)。
- 徒步:一个罗盘方位角告诉你朝哪个方向走,即使在雾中。
You've got it
- a bearing is three figures, measured clockwise from north
- east $090^{\circ}$, south $180^{\circ}$, west $270^{\circ}$
- back bearing differs by $180^{\circ}$ (add if $<180^{\circ}$, subtract if $>180^{\circ}$)
你掌握了
- 一个方位角是三位数字,从北方顺时针测量
- 东 $090^{\circ}$,南 $180^{\circ}$,西 $270^{\circ}$
- 反方位角相差 $180^{\circ}$(若 $<180^{\circ}$ 则加,若 $>180^{\circ}$ 则减)