[mkgmap-dev] Wishlist: Better multipolygon error reporting

Thu Jul 5 21:03:18 BST 2012

Hi Marko,

> Hi,
>
> Lake Päijänne is probably the largest multipolygon relation in Finland,
> even after I split some named bays to separate natural=bay polygons or
> multipolygons. There is one error that I have not been able to figure
> out. JOSM is not complaining anything if I extract the relation from
> finland.osm.pbf with Osmosis and load to JOSM. The whole area is fully
> within the boundaries of my tile 63240005:
>
> 2012/07/05 21:37:39 WARNING (MultiPolygonRelation): 63240005.osm.pbf:
> Multipolygon http://www.openstreetmap.org/browse/relation/1239779
> [natural=water,type=multipolygon,name=Päijänne] contains errors.
> 2012/07/05 21:37:39 WARNING (MultiPolygonRelation): 63240005.osm.pbf:
> Polygon 4611686018427683240(7P)(31081024[7P]) carries role inner but
> lies inside an inner polygon. Potentially its role should be outer.

This message tells you all, almost :-)
Way 31081024 with 7 points is assigned with the role inner. But it is 
not an inner polygon. It lies completely within way 168463590 which also 
has role inner. This is not allowed in mps. So mkgmap assumes that way 
31081024 has role outer and the tagging is a mistake.

WanMil

>
> Could the message mention a coordinate of the faulty polygon?
>
> I am guessing that this message is due to the Garmin map resolution
> (about 5m). It would be nice to identify the problematic polygon, to
> confirm this. Or, maybe the JOSM Validator is not checking for inner
> polygons that are completely within another inner polygon.
>
> 	Marko