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<div dir="ltr">Hi Marko,<br><br>I've checked a few cases. The typical reason for a message like this:<br>very small shape near http://www.openstreetmap.org/?mlat=60.261495&mlon=24.689112&zoom=17 signed area in high prec map units: 2816<br><br>is a shape close to a tile boundary or a shape that is produced by the mp-relation<br>routines. In the latter case, the routines cut a shape into pieces to remove holes.<br>Sometimes this produces micro-areas when the cutting line cuts the polygon into<br>multiple pieces. Nothing is wrong with the OSM data, and the ShapeMergeFilter<br>is able to merge these micro shapes again.<br>I plan to rewrite that part of the code, but it will require a bit more work, so<br>maybe this has to wait for the next autumn.<br><br>For now, I've just lowered the severity to debug level.<br><br>Gerd<br><br><div>> Date: Mon, 17 Mar 2014 22:45:54 +0200<br>> From: marko.makela@iki.fi<br>> To: mkgmap-dev@lists.mkgmap.org.uk<br>> Subject: [mkgmap-dev] Warnings about hyper-precise multipolygons<br>> <br>> Hi Gerd,<br>> <br>> >if you are talking about the messages from ShapeMergeFilter: A possible <br>> >reason is a self intersecting polygon. The filter assumes that shapes <br>> >are not self intersecting, but it doesn't test this yet.<br>> <br>> About a week ago, I got a message that I thought was about merging <br>> adjacent (non-overlapping) shapes that carry identical tags. I cannot <br>> find such a message now. Here would be two examples of this:<br>> <br>> http://www.openstreetmap.org/browse/relation/1225936<br>> http://www.openstreetmap.org/browse/relation/1232121<br>> <br>> These are hyper-precise multipolygons with two circles. Both the outer <br>> ring (actually, the relation) and the inner ring carry the same tag <br>> landuse=grass. Only the value of the golf=* attribute differs, but this <br>> does not matter to the default style.<br>> <br>> There used to be two polygons for the inner circle: the role=inner <br>> polygon with no tags, and a duplicate polygon with the tags <br>> landuse=grass,golf=green. I deleted the duplicate polygon and moved the <br>> tags to the role=inner polygon. Tomorrow or the day after, I should see <br>> if the mkgmap message is changing.<br>> <br>> There still are a few hyper-precisely mapped multipolygons, for which <br>> mkgmap is emitting messages. It is no problem for me to keep these <br>> relations in my ignore list. I usually monitor the output with "grep -vf <br>> logging.ignore mkgmap.log.0". Many relations that were on my ignore list <br>> are no longer generating errors. Either the data has been changed, or <br>> the higher precision is helping, or both.<br>> <br>> Marko<br>> _______________________________________________<br>> mkgmap-dev mailing list<br>> mkgmap-dev@lists.mkgmap.org.uk<br>> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev<br></div></div>
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