Hi Ticker, I thought I already confirmed that the data that was used to produced water.osm was invalid? See http://gis.19327.n8.nabble.com/special-case-where-splitting-fails-without-a-... I've just committed r4746 in the low-res-opt branch, see my comments in the commit message https://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4746 Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Ticker Berkin <rwb-mkgmap@jagit.co.uk> Gesendet: Freitag, 28. Mai 2021 18:24 An: Development list for mkgmap Betreff: Re: [mkgmap-dev] special case where splitting fails without a log message Hi Gerd I'm coming to the conclusion that water.osm is invalid. I've attached an example part. This goes through the cut-line following the same path in and out, and defines both shape and a hole at the same time, which is impossible without the lines crossing. Ticker