Hi all,

WanMil pointed out that the change in r2610 introduced a bug for large sea areas with islands.
Merging all sea-only rectangles could produce polygons with holes:
sssss
ssoss
sssss

r2613 fixes this. For the above example, two large sea polygons are created instead of one.
Change:
The algo merges rectangles only if the result is a singular area. It also tries to avoid creating
long narrow areas.

The img sizes are not much different to those of r2612, and run time is similar.

Gerd