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I mapped a stream that starts naturally meandering. On its way it is more and more forced into a man made straight bed through agricultural area. In that area the previous mapper tagged it as a ditch.

My question: is it better to stick to stream all along the waterway, or change from stream to ditch at a point?

I already had a look at this question and I think mine in building on that:

asked 09 Feb '22, 23:30

MonsterKlaus's gravatar image

accept rate: 0%

In my opinion a ditch is artificially dug to drain surface water. While this may be also a purpose of your waterway it has primarily already been there naturally, albeit it has been forced into a straight bed. I would leave it as a stream. In case the course has been altered considerably you could think of a canal, too.

Have a look at the short descriptions on the wiki, too.

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answered 10 Feb '22, 07:51

TZorn's gravatar image

accept rate: 15%

Thanks TZorn for your input. I agree with you, I prefer to tag it a stream. That is also most in line with the wiki (I checked this in English and German). Canal I understand is for much bigger waterways.

But one thing I didn't find in wiki or in help: is it best practice to stick to the same tag (stream in this case) all along the flow of the waterway? Or change from stream to ditch once it's appearance is changing downstream? In principle this is about accuracy at a single point versus continuity all along the waterway.

(10 Feb '22, 08:45) MonsterKlaus

It's perfectly fine to change the type along a waterway's course. Many will start as a stream but ultimately become a river. For larger streams/rivers there is usually also a relation covering the complete course which carries the main type.

(10 Feb '22, 11:03) TZorn

I don't see any problem with a stream terminating on a ditch. And in fact I could imagine it becoming a stream again, then a ditch again, etc, on its way to terminating elsewhere. There's no value to continuity in tagging if there's not continuity in the real world.

You might think of the stream as the the water itself, while the ditch is the channel that's been dug. In that case you could say that the stream is flowing through the ditch. The best tag for that IMO is still waterway=ditch.

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answered 10 Feb '22, 13:24

jmapb's gravatar image

accept rate: 22%

Thanks TZorn and jmapb. Makes a lot of sense. Especially when also using a relation covering the complete course carrying the main type (stream in my case).

(10 Feb '22, 17:19) MonsterKlaus

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question asked: 09 Feb '22, 23:30

question was seen: 928 times

last updated: 10 Feb '22, 17:19

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum