updated: 30-May-2011

 Copan Lite for Windows

Bearing Expressions

You can enter bearings explicitly, in whole-circle format or in quadrant format, or implicitly as being the bearing between two specified coordfile points. You can even include a + or – operator in an expression to add a correction or turned angle to, or subtract from, a bearing. A correction, turned angle, or whole-circle bearing is always positive clockwise and negative anticlockwise. Finally, unless the appropriate Program Settings are made, angle units are degrees-minutes-seconds, and bearings are north-based (i.e., north=0).

(Note that while lay people may know bearings as directions, in surveying, a direction usually means an arbitrary angle reading, where an angle is the difference between two directions. Even so, we use cardinal direction below to have the common meaning.)

Syntax

If you measure angles in degrees-minutes-seconds (i.e., 1 circle = 360°), when entering bearings or angles, always use the format dd.mmss. For example, you must enter 24°52'10.5" as 24.52105 and you must enter 30' as 0.30 (or just .3).

If you measure angles in gons or grads (i.e., 1 circle = 400^g), just enter bearings or angles as is (e.g., enter 24.82105^g as 24.82105).

In these quasi-formal syntax definitions, a defined term (outdented) is followed by its definition (indented), with alternative definitions on separate lines or separated by vertical bars. Puzzled? See the Examples.

bearing-expression

bearing

bearing   operator   angle

implied-bearing [. 1 | 2 | 3]     (where .1, .2 or .3 means add ¼, ½ or ¾ circle)

bearing

[operator] angle

quad-bearing

implied-bearing

angle

ddd.mmsss

ggg.ggggg

quad-bearing

N | S | E | W | NE | SE | NW | SW

N | S   acute-angle   E | W     (where acute-angle is ≤ ¼ circle)

operator

+ | –

implied-bearing

from-point-number   ,   to-point-number

,   to-point-number     (valid if the from-point-number is already entered in an appropriate from-point field)

Examples

Table 1:   Degrees-Minutes-Meconds Bearing Expressions.

For the lower half of the table, assume that point 102 is at a bearing of exactly 035° from point 101.

For the last two expressions, assume that 101 is already in an appropriate from-point field.

Table 2:   Gons (or Grads) Bearing Expressions.

For the lower half of the table, assume that point 102 is at a bearing of exactly 035^g from point 101.

For the last two expressions, assume that 101 is already in an appropriate from-point field.

updated: 30-May-2011