I believe all these issues have to do with the way TAH works. The
rendering client does not get to see the whole planet but a small tile
(with a safety margin). If not all the data for a feature are in that
tile the client cannot render it correctly.
This has two effects:
- if a feature does not have a node on the tile (including safety
margin) it won't be rendered. This goes for tiles that are completely
within a (multi)polygon and for features where the nodes are too far
- if a member way of a multipolygon is completely outside the tile it
won't be included in the data and the client does not get to see
it. Then the client cannot even decide which side of the line is
inside the feature. Currently, it simply connects the open ends.
The first problem cannot be solved by the client. One could only
increase the safety margin to catch a few more corner cases. The second
could be solved by the client with downloading incomplete multipolygons.
Ideally, these things should be fixed at the server side. If the server
(mostly TRAPI, I guess) delivers all the data that is relevant for a
tile the client can render it.