Hi Gerd I'd hoped and expected that all polygons were fed into the 'lines' style processing in a similar manner, regardless of their origin as either a closed OSM way or generated by multiPolygonRelation. This would allow simple testing using just 'is_closed()=true' to effect lines around polygons if required. Instead I find that, for a few examples I've looked at in detail, for each outer way in a relation a way is passed into 'lines'. They all have identical tags (from the relation) and is_closed()=false. It is difficult to determine if these correspond directly to the ways in the relation. In the generated map, the line around the area might be in multiple segments, so some logic appears to have merged some of the ways but not others. In my example is seems as if merging has been prevented when the original ways have conflicting tags (maybe just the name=) Given that it isn't possible to differentiate the multiple outer ways when passed in from multiPolygon, why doesn't it just pass in the joined way that will be passed to the 'polygons' processing. Also, assuming that later processing is joining some of these parts, what stops it joining them all. I can give you details of my example if required, but just having: mkgmap:mp_created=true & is_closed()=false {echotags 'mpNotClosed'} in 'lines' then looking for consecutive identical 'Way generated from...' output and checking that there is only 1 output polygon will yield a lot. Another difference between closed ways and multi-polygons is that with a closed way the object is passed through the rules of 'lines' concatenated with 'polygons' and all the facilties of stopping after a match/continue/with_actions work in a nice way, whereas with a multi -polygon, even if it matches in 'lines', it is passed through 'polygons' as well; so extra conditions will is needed in 'polygons' to determine if matched in 'lines' Regards Ticker