[talk-au] Causeways

[Ross Scanlon]

> On Tue, 26 May 2009 07:31:01 +1000
> Liz <edodd at billiau.net> wrote:
>
>> On Tue, 26 May 2009, Delta Foxtrot wrote:
>> > My original question was in relation to concreate slab crossings
>> > which technically aren't fords because they dry far more often than
>> > wet, and they aren't raised at all so they're not bridges.
>> >
>> > I can't find an example of what I mean, I'll have to take a photo
>> > of one and post it online in the next few days.
>>
>> the definition of it being wet is a pommie problem
>> you need rain before they get wet
>> we don't even have a marker for rivers or lakes which are seasonal
>> (ie, usually dry)
>>
>> i'm not at all bothered if you label a ford "ford" when the creeks
>> dry - if the creek had water it would be wet??
>
> I agree Liz, I was just thinking pretty much exactly the same thing a
> few minutes ago when Delta's post arrived. It's totally a factor of
> the state of the watercourse in question.

I agree with Darrin and Liz on this.

The openstreetmap wiki also says "any water" it does not mean that there
has to be water over the ford all the time.  I take this as if there is
water over the ford then a vehicle will have to enter it.

The part that says "The road crosses through stream or river" is more
significant as we mark these (stream or river) whether they are flowing or
not so if the road passes through it rather than over it on a bridge then
it's a ford.

I would also consider the case where some roads have pipes (< 1m dia) that
run under the road so that when water level is low as it runs under the
road but with rain in the area it readily flows over the road.  The road
also drops down to just above, or becomes part of, the river bed as
opposed to staying at or above the river banks.

There is also the situation with large diameter pipes (>1m dia) where the
road stays well above the river bed and is at the same height as the
banks.  I've always thought of these as culverts but as osm has no
definition for this I have marked them as bridges as that's generally what
they are.

It's either a ford or a bridge that you cross through or cross over a
stream or river on.  A bridge does not require that you drive through the
water if there is water flowing in the stream or river, a ford does even
though some may have pipes under them as well.


Cheers
Ross