[Tagging] Drain vs ditch

[Eugene Podshivalov]

The confusion is mainly in the difference between irrigation canals vs
irrigation ditches and drainage diches vs drains.

In practice wide irrigation channels are called canals whereas small ones
are called diches and people tend to tag them as such.
This tendency is enforced by the fact that canals and diches are rendered
in difference size.
IMO there is no problem here, we should just document this usage properly.

Drainage diches and drains are confused simply because of their identical
definition on the waterway wiki page
https://wiki.openstreetmap.org/wiki/Key:waterway
drain - An artificial free flow waterway used for carrying superfluous
water like storm water...
ditch - An small artificial free flow waterway used for carrying
superfluous water along paths or roads for drainage purposes

If I did not read their proper wiki pages I would think that they differ
only in size with ditches being smaller than drains.
A tricky thing is that both drains and drainage ditches are used alog paths
or roads but we call it a drain only when it is part of a system of
collecting and disposing of rain water in an urban area as described at
https://en.wikipedia.org/wiki/Storm_drain

So again we just need to properly document the meanings of these tags.

Eugene

сб, 12 янв. 2019 г. в 19:40, Markus <selfishseahorse at gmail.com>:

> On Fri, 11 Jan 2019 at 21:03, François Lacombe
> <fl.infosreseaux at gmail.com> wrote:
> >
> > Regarding ditch, it regards both useful and waste water.
>
> While true in English usage, waterway=drain apparently was intended
> for artificial waterways removing undesirable water:
>
> https://lists.openstreetmap.org/pipermail/tagging/2018-August/038505.html
>
> See here for the whole discussion about 'How to tag small canals?'
> from August 2018:
>
>
> https://lists.openstreetmap.org/pipermail/tagging/2018-August/thread.html#38452
>
> If you want to extend the meaning of waterway=drain to also include
> artificial waterways, how do you intend to differentiate them from
> waterway=canal?
>
> Regards
>
> Markus
>
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