[Tagging] waterway=penstock to complete pipeline tagging

François Lacombe fl.infosreseaux at gmail.com
Mon Oct 5 12:43:19 UTC 2015

2015-10-05 14:10 GMT+02:00 Christoph Hormann <chris_hormann at gmx.de>:
> On Monday 05 October 2015, François Lacombe wrote:
>> Hi all,
>> How would you feel about considering waterway=penstock beside of
>> waterway=canal, waterway=drain to complete pipeline tagging scheme ?
> Not such a good idea - that would be correctly tagged as
> man_made=pipeline.

My words may be unclear.

What I propose : (man_made=pipeline + substance=water) +
waterway=penstock or waterway=penstock + tunnel=yes or...

A water carrying pipeline isn't always a penstock.
A penstock isn't always a pipeline : sometimes shielded tunnels are
directly digged in rock.

> A short tubed section of a regular waterway like below a bridge or dam
> can be tagged waterway=* + tunnel=yes, a longer tube should always be
> man_made=pipeline.

According to you, waterway=drain shouldn't exists ?
This is precisely what is mapped here :
waterway=drain may just be a bare tunnel digged in the rock without
any pipe, thus man_made=pipeline shouldn't be used.
Let's say it's an underground river if anyone is more at ease with it
like here : http://images.lesechos.sdv.fr/archives/2010/LesEchos/20755/ECH20755024_1.jpg

A pipe may be replaced on purpose instead of a drain... or a shielded
penstock digged in the mountain, aren't they ?

> waterway=penstock would also lack any functional distinction that would
> normally be encoded in the waterway tag - data users would have no way
> to decide how treat such feature.  It would just say 'this waterway is
> tubed' not what kind of waterway it is (artificial/natural, clean/dirty
> water etc.)

waterway=canal and waterway=drain don't give those details too : would
you be able to say if the water is clean or waste when waterway=canal
used ?
A penstock isn't a drain, isn't a canal or a river : it's a shielded
tube (not always a pipe) carrying water down a mountain to obtain a
high pressure flow. What more functional details can we give regarding
this definition ?



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