Hello Guys,

I am brewing custom maps for my Garmin zumo 396.

- get the OSM data from the overpass api (0.5 by 0.5 degree bounding box)
- use splitter to split too large parts
- use mkgmap to build the maps.

The generated garmin maps have wrong filled polygons, lakes are filled with land and vice versa.
Here are two examples (lake Balatom and lake Geneva)

http://www.informatik.hu/balaton.jpg
http://www.informatik.hu/geneva.jpg

When I download the lake Balaton in one bounding box the artefacts are disappearing, thus there must be something merging the files.
I have tried various mkgmap settings but could not solve the issues. Curret config is:

levels: 0:24, 1:22, 2:20, 3:18, 4:16, 5:14, 6:12, 7:10
add-pois-to-areas
add-pois-to-lines
adjust-turn-headings
bounds: ../bounds-latest.zip
check-roundabout-flares
check-roundabouts
copyright-message: Map data © Openstreetmap.org
drive-on=detect,right
generate-sea: land-tag=natural=background
gmapi
gmapsupp
housenumbers
ignore-maxspeeds
index
keep-going
latin1
link-pois-to-ways
location-autofill: is_in,nearest
make-opposite-cycleways
merge-lines
name-tag-list: int_name,name:en,name:hu,name,place_name
#nsis
order-by-decreasing-area
precomp-sea: ../sea-latest.zip
preserve-element-order
process-destination
process-exits
reduce-point-density-polygon=8
reduce-point-density=3
remove-ovm-work-files
remove-short-arcs
road-name-pois
route
# show-profiles: 1
style-file: ../styles
style: default
tdbfile
x-split-name-index
verbose

Do you have any ideas what can cause the issue?

-- 
Br,
Vuki