Update documentation of parallel offset
Explain how left and right of parallel offset is determined
@@ -1676,8 +1676,9 @@ linestring feature (right).
object on its right or its left side.
Distance must be a positive float value. The side parameter may be 'left' or
- 'right'. The resolution of the offset around each vertex of the object is
- parameterized as in the buffer method.
+ 'right'. Left and right is determined by following the direction of given
+ geometric points of the LineString. The resolution of the offset around
+ each vertex of the object is parameterized as in the buffer method.
The join style is for outside corners between line segments. Accepted integer
values are 1 (round), 2 (mitre), and 3 (bevel). See also
