I found a problem in the rendering of areas covered by water. On the one hand some islands are filled with water on the other hand some lakes aremissing. Here are two examples, both in Berlin, Germany. The exact position is a few posts further down.
Hello matthias, thanks for report - in the first case it looks like the multipolygon Relation id=3396 does not contain island Schwanenwerder (Wayid=14662281). It does contain islet Imchen (Wayid=14662287) ... in this case I think it is an issue of source data, but I am not sure. Maybe islands automatically generate water boundary??
In the second case it looks like the "water attribute" is set in Way id=10295991as well as in Relation id=5007. We use both and they cancel each other when drawing. This is MapFactor issue and it is caused by inconsistency of tagging (sometimes are tagged ways, sometimes relations, sometimes both and in worst case relation + some of the ways), and it needs some kind of post-processing.
Thanks for the reply. I think all vector renderers that use OSM data struggle or struggled with that issue. Even Google Maps with its own database has some problems with water areas.