updated: 21-Sep-2010
A fairly sophisticated set of options exists for entering distances (radii or lengths) into Copan. A similar set of options also exists for entering offsets, where an offset is a relatively short distance left or right of, and perpendicular to, a particular bearing or line.
You can enter distances and offsets explicitly as values or implicitly as being the distance between two specified coordfile points.
You can even include a simple arithmetic operator in an expression to add, subtract, multiply or divide a distance or offset by another value.
An offset is always prefixed with an L
, R
, –
or +
character.
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.
In the following tables, note that case doesn't matter and that spaces are not required. Also, assume that point 102 is at a distance of exactly 25 from point 101.
Expression | Distance | Explanation |
---|---|---|
10.2 | 10.2 | explicit distance |
10 + 2 | 12 | distance plus distance |
10-2 | 8 | distance minus distance |
10*3.5 | 35 | distance times factor |
10/2.5 | 4 | distance divided by divisor |
101, 102 | 25 | implied distance from point 101 to point 102 |
101,102+6 | 31 | implied distance, plus distance |
101,102/5 | 5 | implied distance, divided by divisor |
, 102 | 25 | implied distance from point 101 to point 102 |
, 102 -4.5 | 20.5 | implied distance, minus distance |
For the last two expressions, assume that 101
is already in an appropriate from-point field.
Expression | Offset | Explanation |
---|---|---|
+ 3.5 | R 3.5 | offset right, explicit distance |
L 5 | L 5 | offset left, explicit distance |
-5 | L 5 | offset left, explicit distance |
R6.4/2 | R 3.2 | offset right, distance divided by divisor |
r101, 102 | R 25 | offset right, distance implied (from 101 to 102) |
l 101,102/2 | L 12.5 | offset left, implied distance divided by divisor |
r , 102 | R 25 | offset right, distance implied (from 101 to 102) |
+ , 102 / 5 | R 5 | offset right, implied distance divided by divisor |
For the last two expressions, assume that 101
is already in an appropriate from-point field.
updated: 21-Sep-2010