Proposed features/railway:signal:height

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railway:signal:height
Proposal status: Draft (under way)
Proposed by: Dakon
Tagging: railway:signal:height=*
Applies to: node
Definition: height of all signals at this node that do not have a dedicated :height subtag given
Statistics:

Drafted on: 2021-12-30

Proposal

It is very common to mount multiple railway signals at the same pole. The (relative) height of them has been given by a :height subtag for each of the types, which can cause a lot of subtags to be needed if there are many subsignals at the same pole.

Most of these subsignals share the same height. It is proposed to add a default height tag railway:signal:height=* that will give the height for all subsignals that do not have an explicit *:height subtag set.

If an absolute height is given this means the highest point and all signals are aligned from this point downwards.

Rationale

Adding a combined signal height tag has several advantages:

  • it is easier to maintain as every subsignal will share the given height if not explicitly overridden
  • it is easier to tag, especially for non-railway mappers, as seeing some sort of signal and telling if it is a normal height or dwarf signal is easy without understanding the signs and lamps on it. It also makes tagging easier for railway mappers when a signal can not be correctly identified, e.g. because it is only seen from the back side, but the height can still be given.

Additionally this tagging is already in use in >400 places worldwide at the time of this writing as it's an obvious addition to the existing tagging.

Tagging

Examples

Examples
Object Description old Tagging (shortened) new Tagging (shortened) Comments
node 4617122755 several subsignals of the same height at the same pole
node 3677326893 different height signals at the same pole Tagging this with railway:signal:height=* would be possible for both of the subsignals, although using it for the more important one (i.e. the main signal in this case) would make more sense.

Rendering

To my knowledge the signal height is not used for the rendering anywhere.

Features/Pages affected

External discussions

Originally proposed by AnakinNN in April 2021 on the OpenRailwayMap mailing list.

Comments

Please comment on the discussion page.