[OSM-newbies] highway=traffic_signals

[Dave F.]

Richard Welty wrote:
> there are two different things that can be modelled here:
>
> 1) physical location of traffic lights.
>
> 2) the location/lanes of traffic controlled by the lights.
>
> modeling physical location conforms to a very literal definition of mapping.
> modeling the traffic control conforms to a more logical definition. 

You seem to be saying that 'literal' & 'logical' are mutually exclusive. 
I'm not sure that's true. The literal way can be the logical way.

> a 
> sophisticated
> routing algorithm could use logical modeling to refine a route. it would 
> find
> physical mapping useless as there is not enough information.

I disagree with this - accurate physical mapping provides more info.
If routing can't deal with that data, that's not the fault of the data.

>  the only way to
> make physical mapping useful to a routing algorithm is to add enough
> information to allow the logical control to be inferred, and by the time 
> you've
> done that, what you've really done is modeled both.
>
> so you need to think about why you're modeling traffic control devices in
> order to make the choice. is it about really nice physical rendering, or are
> there perhaps other customers for the data besides renderers, say, routing
> algorithms to name the most obvious one?
>   

I'm not mapping for either. I'm mapping to provide accurate data for 
whoever can make use of it.
I realise what I've mapped is not perfect but it's more accurate than 
before.

I keep being told OSM is a database not a map & if something is physical 
it can be mapped.
I think I agree with both of those.

Cheers
Dave F.