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[mkgmap-dev] How to split polygons into boundary relations with common ways?

From Marko Mäkelä marko.makela at iki.fi on Tue Jan 24 12:55:21 GMT 2012

This is somewhat off-topic for mkgmap, but I was thinking that perhaps 
WanMil or someone else has worked on something similar.

I got some boundary data. I converted a tiny part of it from Spatialite 
to *.osm polygons with a self-made Perl script. There were some errors 
in the data, such as nodes very close to each other, or some boundary 
had one point less than the adjacent boundary. I fixed these in JOSM, by 
merging the too close nodes, or adding the missing nodes to boundaries.  
Already this was a considerable amount of work, because JOSM seems to 
lack a validator test for "nodes too close to each other" when they 
belong to different ways.

Now, the next step would be to split these polygons (circular ways) to 
boundary relations. Each polygon would have to be split to way segments, 
and duplicate way segments should be removed. Then, relations should be 
formed from the way segments for each area. Is there any software or 
algorithm for doing this?

Best regards,


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