additional things that can be part of the definition: - passages through embankments are (in general) not tunnels. - when a road passes over another one, located in a cutting, does not place the lower one in a tunnel (Antwerp ring road) - when the road goes under a waterway, the road is in a tunnel
Again: exceptions will exist and they have to be seen as a rule of thumb, not a hard definition. On Wed, May 29, 2019 at 5:46 AM Marc Gemis <marc.ge...@gmail.com> wrote: > > AFAIK the tunnel=building_passage, this is not a tunnel, but using the > tunnel tag anyway. I guess the same is true for culvert. I would not > try to come up with a definition that is also applicable to those 2. > > Maybe my rule of thumb could be extended somehow for the metrotunnels, > which are clearly underground, and are therefore tunnels. For the mole > pipes, you write "dug out and covered", which is another indication > that it is a tunnel. > > That being said, I guess you will never find a definition that works > 100% of the time, because the real world is just messy. > > On Tue, May 28, 2019 at 11:57 PM Stijn Rombauts via Talk-be > <talk-be@openstreetmap.org> wrote: > > > > Hi, > > > > First: the interpretations given here to 'tunnel' are much more strict than > > the wiki, which leaves much more room for interpretation. A strict > > interpretation of tunnel makes the use of tunnel=yes of tunnel=culvert for > > passages of rivers underneath a road senseless, just as > > tunnel=building_passage. > > > > Second, I hope that you are aware of the consequences of your > > interpretations. Let's use the definition of Marc, which is the most > > elaborated: "I apply the rule: stand on the road, look up, which layers of > > material do you "see" before you reach the sky? Is there earth > > (grond/aarde) that was not placed there artificially, then you are in a > > tunnel.": Then the 'railroad tunnel' between Brussels North and Brussels > > South is NOT a tunnel. It is just a mole pipe (in the words of Gerard). The > > whole thing is dug out, built and then covered with streets, buildings and > > here there a bit of gorund. > > Even a lot of the metrotunnels are made with the 'cut and cover' technique > > and are thus NO tunnels? Ecoduct Kikbeekbron over the E314 is NOT a tunnel? > > Also the examples given by Marc and Tim with such a thin cover are most > > likely made 'cut and cover' and have only 'artificial' things overneath: NO > > tunnels... > > And what do you do with the GEN-constructions at railway 161 in Genval? The > > railway has been covered with roads and parking lots. Also no tunnels? > > On the other hand: ecoduct Groenendaal really looks like a bridge but has > > been mapped as a tunnel... > > > > Lionel said : "A tunnel is generally something that was dig (removing > > earth/material) and consolidated from the inside (most often with concrete) > > like a subway tunnel if you want. It seems pretty rare to dig a big hole, > > make a tunnel and put back the earth on top !": Yet, that ís a very common > > practice... > > > > So to me these seem to be useless definitions... > > > > Or does the word 'artificial' means that ground level matters? The ringway > > around Antwerp (R1) is almost everywhere at level -1, below ground level. > > The cutting is here the artificial structure (using Yves' words this time). > > So where there is a road going overneath, the ringway goes through a > > tunnel...? The same for Joost's example: if you look at the aerial imagery, > > you can see clearly they had to dig out the N28 to get underneath the > > railway and the other roads: thus a tunnel...? And what about the complex > > traffic changers where it is often very hard to see what the original > > ground level was. > > > > @ Yves: 'Layer' gives a relative position. Something at ground level can > > perfectly have layer=-1 or layer=1. Check the wiki. And further: a bridge > > with layer = 1 doesn't mean it is above ground level; a tunnel with layer = > > -1 doesn't mean it is below ground level. > > > > @ Tim: What came first is a useless criterion. The E313 was constructed > > before the E314, but it is definitely a bridge of the E313 above the E314. > > And the definitions of bridge or a tunnel should be so that anyone knows > > whether to map things as bridge or tunnel without having to know in which > > order roads, railways, etc. were constructed. > > > > So can someone can come up with a useful definition? > > > > Can I come up with a definition? I like the length/width ratio, the open > > bridge(like) structure against a confined tunnel(like) structure. And the > > fuzziness of the wiki. But one thing is very clear for me: ground level > > doesn't matter. > > > > Regards, > > > > StijnRR > > > > > > > > Op dinsdag 28 mei 2019 18:52:50 CEST schreef Marc Gemis > > <marc.ge...@gmail.com>: > > > > > > This is the place: > > https://www.google.com/maps/@51.2216551,4.0345363,3a,75y,49.39h,77.96t/data=!3m6!1e1!3m4!1sjggCIzrpgLhVFtrn6gYCnQ!2e0!7i13312!8i6656 > > (sorry no Mapillary images yet). > > > > Burchtakker (the parallel road) is lowered near the (bicycle) tunnel > > under the E34/A11. > > > > On Tue, May 28, 2019 at 6:36 PM Marc Gemis <marc.ge...@gmail.com> wrote: > > > > > > I think there is a tunnel under the e34 between Antwerpen en Zelzate. > > > There used to be a level crossing which was removed and instead they > > > created an underground passage for it. > > > > > > M > > > > > > Op di 28 mei 2019 14:46 schreef Lionel Giard <lionel.gi...@gmail.com>: > > >> > > >> @joost schouppe To me that's indeed a bridge, as you see the same > > >> structure as on the motorway bridges : a platform supported by > > >> pillars.... > > >> > > >> A tunnel is generally something that was dig (removing earth/material) > > >> and consolidated from the inside (most often with concrete) like a > > >> subway tunnel if you want. It seems pretty rare to dig a big hole, make > > >> a tunnel and put back the earth on top ! ;-) > > >> > > >> I can't find example of tunnels that's really like "under a railway or > > >> motorway", so i would say that probably 99% of the tunnel are below > > >> ground or mountains/hills (if we exclude the obvious building passage > > >> that we classify as tunnel in OSM). They are generally longer than wide > > >> as someone quoted from wikipedia. > > >> > > >> _______________________________________________ > > >> Talk-be mailing list > > >> Talk-be@openstreetmap.org > > >> https://lists.openstreetmap.org/listinfo/talk-be > > > > _______________________________________________ > > Talk-be mailing list > > Talk-be@openstreetmap.org > > https://lists.openstreetmap.org/listinfo/talk-be > > _______________________________________________ > > Talk-be mailing list > > Talk-be@openstreetmap.org > > https://lists.openstreetmap.org/listinfo/talk-be _______________________________________________ Talk-be mailing list Talk-be@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-be
