updated: 21-Sep-2010

 Copan for Windows

Shift Expressions

It is easy to enter an implied shift (translation or slide) from one point to another.

Syntax

In these quasi-formal syntax definitions, a defined term (outdented) is followed by its definition (indented), with alternative definitions on separate lines.
shift-expression
point-number   separator   point-number
point-number
separator
, |

The implied shift is always from the first point to the second point. A single point number implies a shift from it to the origin and is rarely used. Puzzled? See the Examples.

Examples

Assume that these points exist:

Point Northing Easting Elevation
1 100 100 10
2 120 110 12
3 130 90 

The following shift expressions would yield these shift vectors (the first four all being equivalent):

Expression Northing shift Easting shift Elevation shift
1,2 20 10 2
1 , 2 20 10 2
1-2 20 10 2
1 -2 20 10 2
2 - 1 -20 -10 -2
2 - 3 10 -20 0
3 ,1 -30 10 0
3 -130 -90 0
2 -120 -110 -12

updated: 21-Sep-2010