[OSM-talk] [tagging] Feature Proposal - RFC - waterways/ditch

[Andy Robinson (blackadder-lists)]

Tristan Scott wrote:
>Sent: 01 September 2008 4:43 PM
>To: talk at openstreetmap.org
>Subject: Re: [OSM-talk] [tagging] Feature Proposal - RFC - waterways/ditch
>
>the Waterway=Drain tag has this description:
>A Drain is an artificial waterway used for carrying storm water or
>industrial discharge.

Don't read too much into the description, that was just one person's
interpretation. ditches and drains all move groundwater, whether it run off
the surface or migrates to them through land drains (the pipes that drain
the fields).

Ditch and drain could be interchangeable, I used drain in the original map
features because the organisations that are responsible for most of them in
the UK are called drainage boards.

If water just "sat" there they would be of any use. In reality they do move
water, just very slowly.

Cheers

Andy

>
>To me, that seems unrelated to the ditches I have in mind:
>they don't carry storm water - normally the water table won't move
>much in a storm (at least in the UK) and the ditches stay were they
>are. They contain natural rainwater or saltwater from the marshes.
>Secondly, they don't really drain so much as just sit there - the
>fields around stay wet, the water doesn't really move. They're used as
>fences as much as somewhere to connect field drains to.
>here's a pic that seems to illustrate what i have in mind:
>http://web.ncf.ca/bf250/images/odditch.jpg
>
>It strikes me that tagging as drain loses the information that drains
>are usually empty unless draining something (like a storm) and also
>tend to be channels for water movement rather than just sort of long
>thin ponds, though I suppose we must lose information somewhere to
>avoid tag congestion.
>Maybe modifying and clarifying the scope of the drain tag would do?
>Thoughts?
>
>Tristan
>
>2008/9/1 Andy Robinson (blackadder-lists) <ajrlists at googlemail.com>:
>> Tristan Scott wrote:
>>>Sent: 01 September 2008 3:37 PM
>>>To: talk at openstreetmap.org
>>>Subject: [OSM-talk] [tagging] Feature Proposal - RFC - waterways/ditch
>>>
>>>This is a request for comments (my first, so let me know if i've done
>>>it wrong!) on my waterway/ditch.
>>>http://wiki.openstreetmap.org/index.php/Proposed_features/Ditch
>>>
>>>mainly as there's a large area of marshes around where I live, and the
>>>canal waterway tag is completely inappropriate for the still overgrown
>>>drainage ditches (too wide to jump, too overgrown and narrow to
>>>navigate, and not even remotely canal-like)
>>>I can get organised with a picture of the ditch if that's necessary.
>>>Note that ditchs are occasionally "slubbed" out, but every ditch i
>>>know of is more than 50 years old - so it's not as if they're
>>>seasonal.
>>>
>>>oh, and they're on Ordnance Survey maps as thin blue lines, if that's
>>>relevant.
>>
>> Map Features has always had a waterway=drain tag which was always
>intended
>> for drains and ditches. I've been using that when I come across one.
>>
>> Cheers
>>
>> Andy
>>
>>
>>
>
>
>
>--
>Tristan Scott BSc(Hons)
>Yare Valley Technical Services
>01603 858441
>07837 205829
>
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