[Tagging] Drain vs ditch

Eugene Podshivalov yaugenka at gmail.com
Sun Jan 27 10:35:42 UTC 2019


When drain and ditch were originally introduced, was it supposed to
differentiate them in size?
If you read the current definitions closely you can notice the following:

https://wiki.openstreetmap.org/wiki/Key:waterway
ditch - An *small* artificial free flow waterway used for carrying
superfluous water along paths or roads for drainage purposes.

https://wiki.openstreetmap.org/wiki/Tag:waterway%3Dditch
See also - waterway=drain: *for larger* artificial waterways used for the
drainage purposes, and typically lined with concrete or similar

Cheers,
Eugene


чт, 24 янв. 2019 г. в 14:57, Peter Elderson <pelderson at gmail.com>:

> Same here. Drains we don't have that much (almost none), but many many
> ditches of all sizes ('sloot') and canals of all sizes ('vaart', 'gracht',
> 'singel').
> They carry and store water to and from the land: the whole system is
> designed to keep ground water levels fixed in dry times as well as wet
> times, no matter how extreme.  So the flow direction is not fixed and the
> waterways are used for land drainage, irrigation, fire brigades, drinking
> water for cattle, boats and canoes, dumping bodies, murder weapons and
> broken bikes, and at times, ice skating. No single dedicated use.
> The consequence of mapping all ditches as ways is that in z19 on OSM carto
> the land look almost water-less, while in z14 the amount of water looks
> much higher than it actually is.
>
>
>
> Vr gr Peter Elderson
>
>
> Op do 24 jan. 2019 om 12:24 schreef Eugene Podshivalov <yaugenka at gmail.com
> >:
>
>> The question that still remains is: what does "small" and "large" mean?
>>
>> I daresay there is no way and no need to clarify the meanings of "small"
>> and "large" for artificial waterways. We can leave this up to the user to
>> decide on it.
>> Even the definition of a steam as "you can jump over it" is not really
>> observed. You can jump over a 1-1.5 meter waterway but people are tagging 3
>> meter wide waterways as steams as well because otherwise there would be a
>> big difference between the stream 1-1.5 and river 1.5-10 meter width ranges
>> (waterways greater than 10m can already be mapped with waterbodies, so I
>> don't mention them there).
>>
>> In the place where I live drainage ditches and drains can be from 0.1 to
>> 5 meters wide, and anything greater then that can be called a canal.
>>
>> Cheers,
>> Eugene
>>
>> вс, 20 янв. 2019 г. в 01:22, Markus <selfishseahorse at gmail.com>:
>>
>>> On Wed, 16 Jan 2019 at 13:40, Eugene Podshivalov <yaugenka at gmail.com>
>>> wrote:
>>> >
>>> > ditch - Small artificial free flow waterways used for irrigating or
>>> draining land as well as for deviding land. Irrigation ditches can be lined
>>> or unlined, drainage ditches are usually unlined. Consider using
>>> waterway=canal for large irrigation or land drainage channels. Consider
>>> using waterway=drain for lined superflous liquid drainage channels.
>>>
>>> I would even go one step further and abandon waterway=drain.
>>>
>>> The question that still remains is: what does "small" and "large" mean?
>>>
>>> Regards
>>>
>>> Markus
>>>
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