[mkgmap-dev] Merging adjacent multipolygons

Thu Feb 25 11:45:48 GMT 2010

Hi Apollinaris,

> Osmarender has problems with mp on the tile boundary of a rendered  
> area. you can check the tile size at zoom level 12 to see if the lake  
> crosses it. It happens even for very small mp but it doesn't happen  
> all time.

Thank you for your insight.

At  
http://www.openstreetmap.org/?lat=62.896&lon=27.6889&zoom=12&layers=0B00FTF
the coastlines are crossing such tile boundaries. Saimaa is a huge  
lake, even after me splitting the waters :-)

I reported this issue at  
http://wiki.openstreetmap.org/wiki/Osmarender/Development because I  
knew no better place.

I would not yet split the multipolygon further if it is clearly a tool  
issue. Mapnik and OpenCycleMap look fine, but it is currently unclear  
if they are is drawing the water from old coastline-based shape files  
or from the multipolygon definitions.

Best regards,

	Marko