[Tagging] Is the difference between power station and sub station clear?

Ole Nielsen on-osm at xs4all.nl
Fri Jan 25 19:23:20 GMT 2013

On 25/01/2013 19:23, Janko Mihelić wrote:
> 2013/1/25 fly <lowflight66 at googlemail.com
> <mailto:lowflight66 at googlemail.com>>
>     but I also see a problem with using power=sub_station for all now. I
>     think there
>     is a difference between big substations and the real small ones
>     (tagged with as
>     substations right now). Even if it is only a difference in voltage,
>     we will
>     loose this information. Also I would have to either tag the object
>     as substation
>     and transformer or add another node for the transformer (rarely
>     visible) within
>     the closed way.

People should NOT start retagging existing 'stations' without adding a 
voltage tag!

> We can use a medium solution and introduce these values for voltage:
> voltage=low, voltage=medium, voltage=high. Those can than be shown on a
> map as an error (like fixme=*), and mappers will have to put real
> voltage instead of these.

That is a resonable solution. I sometimes do this for transformers when 
I know the higher voltage but not the lower voltage, such as 
voltage=60000;medium. There should probably be written some guidence in 
the wiki on when to use voltage=high and voltage=medium.

But still I wouldn't recommend retagging without reviewing each 
substation individually. In some areas the distinction between large and 
small substations may have been tagged consistently. In my areas of 
interest (Denmark, Netherlands) the use of 'station' was a big mess with 
the tag being put on anything from small transformer buildings to big 
power plants.

>     Think we aswell need a tag for power plants as I often have problems
>     to tag the
>     power=generator on big power plants and some even have more than
>     one. Where
>     should I add my tags, to the real generators or the whole area ?
> I think power=generator was meant to be used as power=sub_station, so
> the whole area. Problem is that power plants often have many parts,
> especially hydro power plants (landuse=reservoir, man_made=pipeline,
> power=sub_station, power=generator, numerous other buildings). Which
> ones are contained in the power=generator area? We should make a better
> wiki page for those.

It is a little bit sad that the proposal 
died due to lack of votes. It would have resolved these problems. Maybe 
somebody could review and eventually improve it and put it forward for a 
new vote (this time advertised properly).

>     As the power=* tags seem to be more isolated than some other tags it
>     might be
>     possible to try a complete but carefully redesigning once we have
>     clarified the
>     meanings and there translations.
>     This will hopefully include correcting misspelled tags.
> I agree. We could add the tag power=substation to the wiki and patiently
> wait for mappers to adopt it. And in a few years, we could do to
> power=sub_station what we are doing now to power=station :)

May be a good idea. It would be crucial to convince the Mapnik 
stylesheet maintainers to support that tag. Otherwise the adaptation may 
be very slow (the chicken and egg dilemma). Mappers like to see their 
data rendered.


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