[Tagging] Waterway direction

[Anthony]

On Wed, Sep 1, 2010 at 3:30 PM, SomeoneElse <lists at mail.atownsend.org.uk> wrote:
>  On 01/09/2010 20:24, Anthony wrote:
>>
>> All the
>> examples of waterways on that wiki page are open.
>
> Well; normally open -
> http://www.openstreetmap.org/?lat=53.327&lon=-1.74192&zoom=14 is an example
> of a bit of canal that isn't

Can you pardon my laziness and tell me whether or not the water in
that part of the canal fills the entire tunnel.

Because, after I wrote that, I thought of that as a possible
exception.  Yes,
http://www-tc.pbs.org/wgbh/buildingbig/wonder/structure/images/worsely1_tunnel_1.jpg
is a waterway.  But a storm water pipe is not.




On Wed, Sep 1, 2010 at 3:32 PM, John F. Eldredge <john at jfeldredge.com> wrote:
> If a body of water that is not navigable is not a waterway, does this mean that any river
> that contains a waterfall is not a waterway?

The waterfall itself is not a waterway.  At least, not if it's not a
navigable waterfall.

> What about a stream or river that has portions that are too shallow to be navigable, or
> where the current is too rapid?

I'm not sure there are any streams or rivers for which the "current is
too rapid" for them to be considered navigable.

In any case, there's no point in giving lots of examples.  The
definition of waterway (the common definition, not necessarily the OSM
Newspeak) includes navigable.  Not navigable means not a waterway.
"Too shallow to be navigable" means not a waterway.  On the other
hand, I can see quite a lot of room for argument over whether or not a
particular stream or river is "too shallow to be navigable".  In fact,
if you look through court cases in the United States I bet you can
find a few instances where this was litigated!

Ultimately, "navigable" may prove to be too difficult of a
determination for OSM purposes.

> What if it is navigable for only part of the year?

Then it's navigable.

> The wiki page for the waterway tag does not say that a body of water must be navigable
> in order to be classified as a waterway.

No, on the contrary.  It gives examples of non-navigable waterways.
It also gives examples of barriers and calls them waterways.  I think
that's an especially bad idea, doubly so in the case of weir and dam
which are drawn perpendicular to the actual waterway.

On Wed, Sep 1, 2010 at 3:34 PM, M∡rtin Koppenhoefer
<dieterdreist at gmail.com> wrote:
> 2010/9/1 Anthony <osm at inbox.org>:
>> examples of waterways on that wiki page are open.  A culvert is more
>> like man_made=pipeline, type=drain.
>
> yes, but if it is part of a waterway, it would for consistencies sake
> IMHO be better to keep it there.

Yes, but that begs the question.  Is an inverted siphon ever "part of
a waterway"?

And where do we draw the line between waterway and storm drain?  Or
are you suggesting that *all* storm drains should be tagged as
waterways?