Hi Felix,
More bad news: After the additional splitting, my gmapsupp.img grew to 94 MB. Without the added levels and the splitting, it would be about 80 MB. The baseline (without the patch and splitting), it would be about 82 MB. I think that the growth is unacceptable.
I accidentally generated the extra-split map with today's data, using the patch for lines and polygons (but not options). The resulting gmapsupp.img is 83 MB. Without the extra splitting, it was 80 MB yesterday. If we assume that the map has not changed much between yesterday and today, the two extra levels would cost 11 MB, or more than 10%. If we include the "collateral damage" of additional splitting, it really is 14 MB, or 18% additional file size. Would you approve the attached patch? Marko