Symmetric difference
The set of all points of a pair of spatial objects where the objects do not intersect.
The set of all points of a pair of spatial objects where the objects do not intersect. This difference is spatially equivalent to the union of the two objects less their intersection. The symmetric difference contains the boundaries of the intersections.
In the following figure, the shaded areas represent the symmetric difference of the two rectangles.
The following figure shows the symmetric difference of two overlapping linestrings.