If one has two signals on the same pole, but facing different directions, the
current tagging requires to place 2 nodes, one for each direction. I don't
like it, for obvious reasons…
I think I have something that we could work with, and want to her opinions on
it.
For the moment I would like to add a few restrictions to it: this only applies
to signs, and only if the same sign type is used on both sides of the pole.
Common examples are snowplow signals in Germany, where you have the "snowplow
up" on one side and "snowplow down" on the other side of the pole. Another not
that common example are Lf7 signs (speed limits). I can even think of Ne5
(stop inside station) to be shared, and here even if both directions have
different length or not plates on them. The German mappers will hopefully get
what I'm talking about. ;)
So, here is what I propose:
railway signal
railway:signal:direction forward
railway:signal:position right
railway:signal:snowplow DE-ESO:ne7
railway:signal:snowplow:form sign
railway:signal:snowplow:height normal
railway:signal:snowplow:type up
railway:signal:snowplow:type:backward down
This has the usual tagging for the Ne7 snowplow signal. It also has one
:backward, which would override the "type" for the sign mounted on the
backside of the pole, and which for obvious reasons implicitely gets a
railway:signal:direction=backward.
I could think also of something like this:
railway signal
railway:signal:direction backward
railway:signal:position left
railway:signal:stop DE-ESO:ne5
railway:signal:stop:form sign
railway:signal:stop:height dwarf
railway:signal:stop:caption 100m
railway:signal:stop:caption:backward 200m
What cannot be done using this way of tagging is:
-have a property on the forward-looking signal that the backward facing one
does not have, i.e. one cannot "delete" the caption if the forward looking one
has one, but the backward does not. One could simply invert the tagging in
that case and make the backward signal the main one, and only add the property
to the then-backside forward signal.
One case that is not yet shown is when the signal is exactly the same for both
forward and backward. I would suggest "overriding" the type in this case:
railway signal
railway:signal:direction backward
railway:signal:position left
railway:signal:stop DE-ESO:ne5
railway:signal:stop:backward DE-ESO:ne5
railway:signal:stop:form sign
railway:signal:stop:height dwarf
I'm unsure, maybe we should just always override the type in case of a
backside signal, so one does not have to check all tags.
What do you think?
Eike
