Multipolygon strictness

[bdon]

Currently it seems imposm3 will ignore multipolygons that don't meet the current spec:
http://wiki.openstreetmap.org/wiki/Multipolygon_Examples

It looks like other import tools attempt to fix invalid multipolygons, of which there are many, into a usable state (see http://wiki.openstreetmap.org/wiki/Osmium/Multipolygon)

In my experience there can be some funkiness with missing riverbanks after imposm3 imports. I was wondering if the imposm3 authors and other users are interested in more forgiving multipolygon support (with the tradeoff being, a messier implementation).

[olt]

Do you have any examples?

Imposm should handle almost all multipolygons. It supports whats is listed in the Osmium wikipage (self-intersection, wrong/missing inner/outer roles, etc.). The only thing that it doesn't support and that I'm aware of are unclosed polygons.

[bdon]

OK. I'll have to keep better track of how exactly the multipolygons i'm seeing missing are malformed. Will reopen issue when I come across one. Thanks, i wasn't aware that all the osmium cases were already covered.

[olt]

Polygons are now merged if there is a single gap and if the gap is not larger than ~0.1m. This should fix a few more invalid polygon cases.