[mkgmap-dev] Analysis of MP issues in Finland

Fri Jan 29 12:01:19 GMT 2010

Hi WanMil, Mark, all,

I analyzed all the multipolygon errors and warnings I got for today's
finland.osm.bz2 from Geofabrik, without --generate-sea.  

Most of them can apparently be blamed on missing boundary information.
I wrote the relation IDs an explanations to my logging.ignore file, so
that I will not have to see these messages again.  You can get the file
from http://www.polkupyoraily.net/osm/,
but I will repeat the interesting bits here:

# overlapping lines in multipolygons, should be fixed in mkgmap later
http://www.openstreetmap.org/browse/relation/48542
http://www.openstreetmap.org/browse/relation/367049
http://www.openstreetmap.org/browse/relation/372975
http://www.openstreetmap.org/browse/relation/387793
http://www.openstreetmap.org/browse/relation/389976
# multipolygon problem at tile border, should be fixed in mkgmap or splitter
http://www.openstreetmap.org/browse/relation/302897
http://www.openstreetmap.org/browse/relation/306274
http://www.openstreetmap.org/browse/relation/311221

(the offending tile border is at lat=62.226562;
the other one is at lat=64.819336)

I could not see what is causing the following issues.
WanMil, can you please analyze these?  One of them was edited recently,
but the other was not, as far as I can tell:

2010/01/29 12:11:44 WARNING (MultiPolygonRelation): 63240001.osm.gz: Multipolygon http://www.openstreetmap.org/browse/relation/372970 contains intersected or overlapping ways
2010/01/29 12:11:44 WARNING (MultiPolygonRelation): 63240001.osm.gz: Multipolygon http://www.openstreetmap.org/browse/relation/375636 contains intersected or overlapping ways

Last but not least, here is an idea for quality control.
I came across two lakes whose islands were in another lake
(the change message hinted that the lake had been split).
There is no warning for that.  The errors must be coming
from missing boundary information in the Geofabrik extract.

http://www.openstreetmap.org/browse/relation/303320
http://www.openstreetmap.org/browse/relation/303321

Best regards,

	Marko