On 07-Mar-18 08:55 PM, NKA mapper wrote:
Thank you for you comments, Warin. Please see my discussion inserted below.

Wed, 7 Mar 2018 08:48:22 +1100
From: Warin <61sundow...@gmail.com <mailto:61sundow...@gmail.com>>

> The obstacle is not the light, but the light is used to mark it.
> Perhaps air_obstacle=tower/line (thinking of power and communication
> lines as well as towers)
> If you want to identify air obstacles, if you only want to identify
> those obstacles that have identifiers then

You are right, the light is not the obstacle. However, I am not trying to tag nor identify all the obstacles. All the obstacles are already defined in OSM as man_made=tower, man_made=mast, man_made=chimney, building=* etc. I would just like to tag the warning light on the obstacle - that is the scope of the proposal. A previous proposal some years ago tried to identify the man_made features as aviation obstacles, but it met considerable resistance and failed.

> Some of these have lights, some have no lights. Some lines have soccer
> ball things in bright colours.
> For that maybe airmark:light=yes/flashing_red/* airmark:ball=red/*

Correct, many obstacles are required to be marked with paint for daylight identification, typically aviation red/white horizontal stripes. Power lines across gorges may be required to have "soccer balls". However, in this proposal I only focus on the lights.

Good. But consider the future extension to 'soccer balls' and maybe other things.
I think what you want is something like airmark:light=*

> conditional tagging could be used ..
> light_source:conditional=high intensity flashing white
> light@sunrise-sunset:low intensity flashing red light@sunset-sunrise
> https://wiki.openstreetmap.org/wiki/Conditional_restrictions <https://wiki.openstreetmap.org/wiki/Conditional_restrictions>

Yes, I am sure this approach would be possible. However, combining all the various attributes (colour, intensity, character, day/night, ICAO type, multiple) into one line would lead to a complicated syntax without any error checking in the editors and with a high probability of getting it wrong.
The day/night is the conditional thing .. and there is already a syntax for that. So no need to invent another syntax to do the same job in a different way.

The syntax for the light ... has that not already been done for seamark?

For certain obstacles, such as light masts around a stadium, it would be necessary to use the light tag for the main (flood)light on the mast and the obstacle_light tag (or airmark:light tag) for the (flashing red) warning light on top of the mast. Also, all the obstacles close to the sea already have a defined scheme for tagging the various light attributes in the seamark:light feature, which I try to build on in the proposal.

As the obstacle is not being tagged - leave that word out. What is being tagged is a warning light for aircraft .. so airmark:light I think is better.
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