>If 2 ways share a node, then they must be connected to each other. ie on the same layer. So one can't be above/below the other. A road and a stream crossing on the same layer is a ford. >If you tag the shared node as a tunnel, then you don't know which way goes through the tunnel. Does the stream go through a tunnel, or does the road go through a tunnel, or both?
>It is much more useful to map tunnels/bridges as a way. If you know there is a tunnel, but don't know how long the tunnel is, you can estimate it. ie based on the width of the road. You can add a note to say the exact >length/position is estimated Excellent explanation. Agree totally. On Thu, Mar 1, 2018 at 7:48 AM, Craig Wallace <[email protected]> wrote: > On 2018-02-28 23:21, Vao Matua wrote: > >> François >> >> I don't have an example. I was trying to think of an example where layer >> would be needed for a stream/road crossing. A pipe would probably be a >> better example. >> >> Sorry to cause a distraction. >> >> My real question is "Why not allow tunnel=culvert to be a node?" >> >> Emmor >> > > If 2 ways share a node, then they must be connected to each other. ie on > the same layer. So one can't be above/below the other. A road and a stream > crossing on the same layer is a ford. > If you tag the shared node as a tunnel, then you don't know which way goes > through the tunnel. Does the stream go through a tunnel, or does the road > go through a tunnel, or both? > > It is much more useful to map tunnels/bridges as a way. If you know there > is a tunnel, but don't know how long the tunnel is, you can estimate it. ie > based on the width of the road. You can add a note to say the exact > length/position is estimated. > > > _______________________________________________ > Tagging mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/tagging > -- Dave Swarthout Homer, Alaska Chiang Mai, Thailand Travel Blog at http://dswarthout.blogspot.com
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