Rendering barriers above highway areas

[kocio-pl]

Resolves #528.

The code is simple - I've just moved 2 barrier layers (line-barriers and area-barriers) after 3 filling layers (highway-area-fill, roads-fill and turning-circle-fill) and it works, but I don't know if there are side effects, so please report any problems.

Warsaw, z19:
Before

After

[pnorman]

We intend to merge highway areas into linear highway fill at some point - how will this interact?

[kocio-pl]

I don't know. You mean the lua branch?

[pnorman]

No, #2046 and the related incomplete PR

[kocio-pl]

Once #2058 is more or less in its releasable shape, I'm happy to test it. But since it looks like you don't have a time to resume this work, I think we can merge this one (if there are no other problems) and look again when the time will come.

[matthijsmelissen]

I am a bit concerned that this PR would mean that hedges etc will cover (and perhaps sometimes completely hide) roads. That might be worse than the bug this is trying to solve?

[matthijsmelissen]

I am a bit concerned that this PR would mean that hedges etc will cover (and perhaps sometimes completely hide) roads. That might be worse than the bug this is trying to solve?

[kocio-pl]

I will check it.

[kocio-pl]

We already show hedges along the roads and I see no such problem. It does not hurt even pedestrian and bicycle ways (which are thinner than roads), for example:

https://www.openstreetmap.org/way/370601787

Let me know if that's what you were asking me, because it seems it has nothing to do with highway areas at all. If it's OK for you, I will fix the code to make it ready to be merged.

[matthijsmelissen]

An example of what I mean:

Taken from here.

[kocio-pl]

Now I see... It's hard for me to judge, both problems look pretty important for me. It would be good to have at least the estimation how often they would appear, but I don't know how to measure it.

[nebulon42]

I think this is undesirable and should be solved by splitting up barriers in things that could show up over roads and ones that shouldn't. Hedges are things that shouldn't show up over roads. Walls could.

[kocio-pl]

If there will be no objection, I will try to do the split.

[matthijsmelissen]

I'm not sure whether walls (and citywalls even more so) wouldn't cause the same problem.

[kocio-pl]

Should we find some examples to test it or we just want to avoid it anyway?

[matthijsmelissen]

Testing in real-life examples never hurts but I'm quite sceptical.

[kocio-pl]

So I'm closing it now. The change is rather simple, so we could easily recreate it once we need it.

[Tomasz-W]

I can see here just one example of barrier hiding the road, but I can give you a lot more of examples, when barrier is not visible, and it could make map user wrong:

1. barriers in the middle of highway area:
   https://www.openstreetmap.org/way/261727797
   http://www.openstreetmap.org/way/289976085
2. guard rails or retaining walls for people in wheelchairs
   https://www.openstreetmap.org/way/498100708
   http://www.openstreetmap.org/way/436542403
   https://www.openstreetmap.org/way/343486650
3. fences and walls crossing highway areas:
   https://www.openstreetmap.org/way/344084296
   https://www.openstreetmap.org/way/440398217
   https://www.openstreetmap.org/way/388928461
   https://www.openstreetmap.org/way/313571600
   https://www.openstreetmap.org/way/441567205
   https://www.openstreetmap.org/way/359999536
   https://www.openstreetmap.org/way/438594618

I think the situation of barrier hiding the road is a lot lot rarer, than situation when lack of barrier line could make someone walk/ ride in wrong direction

[Tomasz-W]

I think it haven't been tested enough (just one example of barrier hiding the road!) and should be reopen.

[kocio-pl]

Due to technical limitations on GitHub it can't be reopened, but the change is simple to do - see #2394 (comment). Is there anyone willing to test it?