[Tagging] Adding values to usage=* key for power transmission

Michael Reichert nakaner at gmx.net
Wed Dec 3 18:55:10 UTC 2014


Hi,

Am 2014-11-23 um 23:09 schrieb François Lacombe:
> As suggested on Talk page of Power transmission refinement proposal, power
> lines and cable should be described with a key giving their usage in the
> network.
> https://wiki.openstreetmap.org/wiki/Talk:Proposed_features/Power_transmission_refinement#line.3D.2A_and_cable.3D.2A:_similarity_and_difference
> 
> I knew usage=* and it can be the ideal key to indicate usage=transmission,
> usage=distribution,... on power lines or power cables.
> But it is currently and exclusively used for railway tagging.
> https://wiki.openstreetmap.org/wiki/Key:usage
> 
> Is it acceptable to extend its definition to power lines or another key
> should be used?
> https://wiki.openstreetmap.org/wiki/Proposed_features/Power_transmission_refinement#overhead_power.3Dline

I am one of the active railway mappers in Germany and work (togehter
with other mappers) on railway tagging. The following is my personal
opinion.

I think that there is no problem do use a key like usage=* for two kind
of objects. There are already some keys in use which spread over several
object "classes", e.g. service=*, maxspeed=*, operator=* or
wheelchair=*. It is used for highway=service to give information which
type of service street it is. If service=* is tagged on a ways with
railway=rail/light_rail/…, it describes that this track is *not* an
important track. Only siding, yard and crossover tracks get service=*.
Tracks of a long railway line running through a station do not get
service=*, they are tagged with usage=*.
service=* is also used for waterways.
https://wiki.openstreetmap.org/wiki/Key:service

I do not know why anyone should tag one OSM way both with power=* and
railway=*. Catenary of a railway track is mapped by tagging
electrified=contact_line, voltage=* and frequency=* onto the railway
way. There are already some ambiguities with maxspeed=* one trams
running in street. These are solved by either mapping the street as two
ways (if a barrier is between) or mapping the tram tracks as two tracks
or (if a circular/one-track tram line) mapping two independent OSM ways
(as a precursor of a future tag set datatype).

Just have a look at banks. A bank can be tagged with atm=yes and
opening_hours=*. What's the solution? Just split the bank into a bank
node and an independent atm node (if atm is 24/7 accessible).

Because usage=* does not say what a OSM way represents, data users
always have to check if it is a railway track or a power line. If a way
has (by accident) only usage=* and neither power=* nor railway=*, this
should be fixed by a mapper looking into OSM object history.

I suggest you not to use network=*. In difference to usage=*, network=*
does not have a fixed set of values. network=* is used (among other
use-cases) for a human-readable name of a bus/tram/train/… network. I
think that mixing free and fixed values in one key is worse than using
usage=* for two categories. Maybe mappers start to map networks like
"Main power network of XY power company" in future. Then mappers would
best use network=* as public transport mappers do.

We should not start at OSM to add a prefix (as namespace) in front of
every tag. What about a mechanical edit changing wheelchair=yes to
restaurant:wheelchair=yes? :-)

Best regards

Michael



-- 
Per E-Mail kommuniziere ich bevorzugt GPG-verschlüsselt.

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