The QUAD directive in a coordinate system definition is used to set the orientation of the coordinate system.
This directive takes an integer value from -4 to 4. 0 or 1 indicate the normal right-handed Cartesian system, where X increases to the east, and Y increases to the north. This is the default quadrant.
Quadrants are numbered counterclockwise:
- a value of 2 specifies a Cartesian system where X increases to the west and Y increases to the north;
- a value of 3 indicates that X increases to the west, and Y increases to the south;
- a value of 4 indicates that X increases to the east and Y increases to the south.
|
2 |
1 |
|
3 |
4 |
A negative value will cause the axes to be swapped after the appropriate quadrant is applied.