OpenStreetMap
I-285 NOT a tunnel where the Hartsfield-Jackson runway bridge goes over
Spisany wot dygituljunky dnja 22 January 2019 w rěči English.Hartsfield-Jackson International Airport needed additional runway space so the built a runway over the existing interstate highway. The structure of the runway is a bridge and there’s no dirt on that bridge. Yet, possibly because of the width of the runway bridge and the neighboring taxiway bridge, several mappers have tagged the segments of I-285 underneath the runway and taxiway as tunnel.
Note that both articles talk about the lower roadway being surrounded by dirt for the case of a tunnel. While both articles do say that it’s a judgement call, the construction methods used absolutely were bridge construction methods. The bridge article warns against using both bridge and tunnel tags to describe the situation and it’s absolutely more of a bridge situation than it is a tunnel situation.
I have messaged the most recent editor asking them to remove their tunnel tags and I’m posting this diary entry for future reference when this inevitably comes up again. Happy mapping, y’all.
Diskusija
Komentar wot Andy Allan spisany dnja 22. January 2019 15:03
Personally, I think it’s reasonable to tag these as four parallel tunnels. From what I see, I would have mapped them as tunnels because each of the lower sections are much, much longer than they are wide, and that’s one of my rules of thumb for ambiguous situations. The first and fourth tunnels indeed have dirt beside them. Having a tunnel wall between two tunnels doesn’t stop them from being a tunnel, so the central pair could be considered tunnels too, even without dirt beside them.
It doesn’t really matter how they were built. Think about all the subway tunnels in London (and elsewhere) that have been constructed by digging a trench and building a platform (or really extensive ‘bridge’) over the top to take roads, parks, buildings etc. The construction methods don’t really matter, they are still considered tunnels.
But most importantly, it’s better to discuss the situation with other mappers, and come to an agreement! Perhaps this is one situation where it’s fine to have both tags? You could talk through it on one of the mailing lists or at a local meetup and see what other people think.
Komentar wot GinaroZ spisany dnja 22. January 2019 21:38
At the moment the runway is a bridge as well as the road below being a tunnel - so one of them needs to be changed.
Komentar wot Warin61 spisany dnja 23. January 2019 00:41
It is a bridge. Nothing in the definition of a bridge specifies its maximum width to length ratio.
dygituljunky I’d place a note on both ways to say the runway is on a bridge, and the road way goes under a bridge - so the road way is not in a tunnel.
Komentar wot TheDutchMan13 spisany dnja 23. January 2019 06:31
I don’t see any reason why both tags can’t be used.
Komentar wot Warin61 spisany dnja 23. January 2019 06:56
So the Waal river is in a tunnel under the under the Zalige Bridge.
Or the Gooimeer (lake) is in a tunnel under the Hollandse Brug (bridge).
I think not.
A bridge does not mean the thing under it is in a tunnel.
Komentar wot Silva1989 spisany dnja 23. January 2019 10:29
I guess tunnel doesn’t fit the real situation here, but bridge does. Adittional tags such as man_made=embankment, barrier=retaining_wall or landuse=grass could be applied though, reinforcing that the highway grounds are lower than the airport’s
Komentar wot althio spisany dnja 23. January 2019 10:45
@Warin61
Nothing currently in osm.wiki/Key:bridge but osm.wiki/Key:tunnel reads:
And if you like “old” archives: - https://help.openstreetmap.org/questions/5934/bridge-vs-tunnel - osm.wiki/Talk:Key:bridge#Bridge_vs_Tunnels
Komentar wot althio spisany dnja 23. January 2019 10:52
@dygituljunky
Surely a very similar situation happens in several places. Some other interesting cases:
I think tagging the way below (
tunnelorcovered) as distinct advantages:Komentar wot Warin61 spisany dnja 23. January 2019 21:42
@althio
“surrounded by earth”… meaning earth on top, as well as the sides and the bottom.
There is no earth on top - on top is the bridge .. so these are not tunnels by that definition.
As for ‘the lower way is long” I would take that ti mean dimensionally greater than the dimension of that section of bridge across the top of it. But for me the more important defining thing is the earth aspect, no earth between the bridge and the thing under it - it is not a tunnel. A tunnel is bored though earth, it does not have a man made thing above it all the way to the surface.
Komentar wot althio spisany dnja 24. January 2019 08:48
@Warin61
Your reading is rather selective. Alright about “surrounded by earth”: I can read and understand that and what it implies.
But it seems that you forget much too easily ALL the context and other words, don’t you?
I agree with the current definition and others before: the “length” (length/width ratio) of the lower way is a interesting piece of information and it is natural to take it into account somehow.
Komentar wot Andy Allan spisany dnja 24. January 2019 09:55
@Warin61 I think you are being too strict on your definitions, and as @althio says, you seem to be a bit selective in your reading.
However, I’d like to hear your opinion on https://en.wikipedia.org/wiki/Transbay_Tube since there is no earth on either side, or on top, and it was not built by boring or mining through the ground. I think many people would consider this to be a tunnel, do you?
Komentar wot Warin61 spisany dnja 24. January 2019 22:25
@Andy… Yes a tunnel :)… If people want to nit pick; Over time it will ‘silt up’ and have silt cover it - thus earth … The ‘earth’ includes oceans, rivers etc .. so water is ‘earth’ …
How is that for a ‘definition’ of ‘earth’?
———————– @althio - even more selective. The simple OSM definition for a tunnel - without all the explanatory words is ‘‘A tunnel is an underground passage for a road or similar’’. The key word there is ‘underground’, to me that means earth above it, beside it and below it. And I would accept water as being part of the earth.