max_parallels_xld — Join modified XLD parallels lying on the same polygon.
max_parallels_xld joins all modified XLD parallels in
ExtParallels into a polygon if they lie on the same
original polygon segment. This means that polygons exhibiting
parallelism and enclosing homogeneous areas in several places are
joined into one long polygon (from the first parallel line to the
last parallel line). The resulting polygons are returned in
Extended XLD parallels.
Maximally extended parallels.