[Tagging] Splitting places and hosted devices in mapping

[François Lacombe]

Le sam. 8 juin 2019 à 17:48, Johnparis <okosm at johnfreed.com> a écrit :

> I disagree with the premise. There is no confict at all between building=*
> and power=*. See https://www.openstreetmap.org/way/142321228 for a
> typical case.
>
Not between building=* and power=* but with power=transformer and
building=* (for instance).
Building is a site/place/facility and power=transformer is a device, just
like power=converter.
power=substation and building=* are perfectly compatible on the other hand.


> This is a very typical situation where there is "stuff inside" the
> building. In this case, it's a single-use building -- a power converter
> building. Yes there are one or more devices inside the building, but that
> doesn't change the building's single use. So no need for guessing where
> nodes might be needed inside the building for the converter device(s). Just
> tag the building itself. (And there doesn't have to be a building -- if
> it's outdoors, just tag the enclosing area.) If you learn more about the
> nature of the converters, you could (for example) have a tag like
> "converter:count=3".
>
I disagree because converters may have different capabilities and figures,
mixing them with the building could lead in a kind of mess.
The global idea of not mixing building and devices unless they are on the
same node really ease the QA and consuming process : you'll get building
and devices separately.
Having rules for single device different from several devices in a building
need to re-qualify building when a device changes whereas the building
hasn't changed in reality.
Mixing devices and buildings make device properties compatible with
building ones while they aren't (and mapping practices are often taken as
truth here). This point is particularly important.
And so on...

Specifically on the topic, a converter hall will never have only one
feature inside : you'll find the converter, but cooling and auxiliary power
stuff also, and all that world should get individual features


> By the way, your last example:
> No tag specifies the output voltage in your example. As I read other
> related pages, I think it should be tagged:
> voltage:primary=63000
> voltage:secondary=1500
>

The example deals with the substation, not with the involved devices (and
voltage:primary is a device property)
power=converter objects will certainly have voltage:primary and
voltage:secondary, not the substation (and mixing them would make
power=substation and voltage:primary apparently compatible while they
aren't, no exceptions)
Furthermore, tagging voltage on the substation is a bad idea, only useful
to ease renders assuming the size of the facility based on the highest
voltage involved.

I know this is a really particular topic, but I try to make it more easy to
handle by making feature separated as to not get the whole bunch at one
time.

All the best

François
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