1# compass-angle
2
3Because of the extensive historical use of compass heading names
4like "north" and "se" (short for "south-east") in PIC and Pikchr,
5it makes sense that angles should be specified according to compass
6degrees.   North is 0° and the angle increases clockwise so that
7east is 90°, south is 180°, west is 270° and 360° is
8back to north again.
9
10~~~ pikchr
11C: dot
12arrow up from C; text " 0°"
13arrow right from C; text "  90°" rjust
14arrow down from C; text "180°" below
15arrow left from C; text "270°  " ljust
16~~~
17
18Even though heading angles are specified in degrees, the arguments
19to the built-in "sin()" and "cos()" functions are in radians.
20