Search TipsMixing Coordinate Systems
Every dataset “knows” which coordinate reference system its items are defined in.
If you overlay two datasets with different coordinate systems into a single SWD, SIS Desktop 9 will do "on-the-fly" conversions between them.
TIP: You can also change the viewing coordinate reference system with CRS (Home > Map).
Datasets will draw faster when their coordinate system matches the viewing projection.
To speed up drawing, SIS Desktop 9 uses a matrix approximation when the difference between a full conversion and a matrix conversion is less than a couple of pixels.