[mkgmap-dev] Broken coastline errors between V1188 and V1398

Tue Nov 24 08:22:24 GMT 2009

>> I can confirm that this problem exists in the newer versions of mkgmap.
>> Some coastlines are missing in the map.

> After playing a little bit with the data, I think it is the
> MP code thats causing the coastline to disappear.
> 
> It seems that the error occurs, when a coastline is member
> of to many boundary-multipolygons. In my test the coastline
> was disappearing when beeing member of more than two
> boundary-MPs.
> 
> So as a workaround: I think for boundary-multipolygons the
> multi-MP handling is not neccecary at all, because
> boundaries (normally) are rendered as lines and not as
> areas.

I hacked a little OSM preprocessor in vb.net (don't speak java)
which does the following:

change type from multipolygon to boundarypolygon for all
MPs with no inner-elements. This eliminates the MP
processing for those boundary polygons.

If someone want's to get it, -> mail me.

Chris