[Tagging] Powerlines underground

[François Lacombe]

2013/1/15 Ole Nielsen <on-osm at xs4all.nl>

>
> Well, I think we need to properly define what is meant by "power=cable".
> The wiki page isn't entirely clear on that matter. I'm usually mapping a
> underground cable connection as a single way tagged as "power=cable" and
> indicating the number of physical cables with "cables=*" (if it is known
> to me).
>

I'm totally aware of that.
But it doesn't explain why we have to represent two equals things with two
different names and two different concepts.
Tags intend to describe reality, not transform data as mappers want it to
appear.

Your interpretation is obviously that each physical cable
> should be mapped as "power=cable" (which you can't if you don't know the
> number of cables).
>
No.
I tried to imagine what we would have to do if we were using "cable" at its
right signification. It's not what I propose.


>
> Considering that "power=line" and "power=cable" are used so extensively
> I think it is a bad idea to redefine the meaning of them as it would
> break a lot of things and confuse mappers. The distinction between 'line'
> for overhead power lines and 'cable' for underground cable connections is
> easily understandable by the average non-expert mapper.
>
It's a point of view.

There are some ways still described with deprecated tags like
power=underground_cable.
They must be modified to conform to current model. "Don't break users
implementation" is not a good reason to keep deprecated implementation with
no limit of time.
*If users want a stable data-set, they download an extract of planet.*


>
> My proposal is to clarify both the 'line' and 'cable' wikis as follows:
>
> "power=line" should represent a connection comprising UN-insulated
> conductors mounted on towers or other supporting structures, normally over
> ground.

"power=cable" should represent a connection consisting of one or more
> insulated cables (whether underground, underwater, in a tunnel or
> overground).
>

But there are some places where non-insulated cables are installed indoor,
like in bridges or even in some dedicated tunnels (like it seems to be in
the Philip Barnes' example).
So what would be the tagging scheme here? power=line (non insulated cables)
or power=cable (indoor case)? It don't make great sense.

Ideally, multi-dimensional tagging must be made by association of several
mono-dimensional range of values.
We have power=line, power=minor_line, etc... but it can't give the
location, which must be defined by another tag.



>
> The number of physical cables for a cable connection should be indicated
> by "cables=*" when known. I'm currently drafting a wiki page for a
> "circuits" tag to describe the number of electrical circuits, especially
> useful for cable connections having an unknown number of cables, see
> http://wiki.openstreetmap.org/**wiki/Key:circuits<http://wiki.openstreetmap.org/wiki/Key:circuits>
> .
>

And I totally agree with you on this side of the tagging scheme :)

Regards.



-- 
*François Lacombe*

francois dot lacombe At telecom-bretagne dot eu
http://www.infos-reseaux.com
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