[Tagging] Giant river multipolygons

Toby Murray toby.murray at gmail.com
Mon Jan 28 17:53:57 GMT 2013


In theory, I like trying to go towards "one feature in the world ==
one feature in OSM" but of course we break that theory a lot by
splitting roads for various reasons. But being able to do a search for
"Danube River" and getting back a single object from nominatim would
be nice.

As pointed out, it isn't really feasible for some large objects. This
could maybe be handled similarly to how route relations are done for
US interstates and national highways. Each state has its own relation
and then they are all grouped into a single master relation. this
reduces edit conflicts and allows you to work with smaller chunks of
the whole thing at a time. Nested relations can be a pain too though.
So... it's complicated :)

Even though I have done the Kansas River (which isn't *that* big) as a
single MP relation, I wouldn't go changing what others have done
locally with large bodies of water.

Toby


On Mon, Jan 28, 2013 at 11:28 AM, John F. Eldredge <john at jfeldredge.com> wrote:
> Malcolm Herring <malcolm.herring at btinternet.com> wrote:
>
>> On 28/01/2013 16:26, Tobias Knerr wrote:
>> >   I'd like to hear your opinions.
>>
>> +1
>> As a developer of both editing and rendering software, such data
>> structures are troublesome. I dislike multipolygons with multiple
>> disjunct outers both as a mapper & as a developer. I have had to
>> abandon
>> edits when warned that I was about to break a multipolygon with 999
>> other members. How can one know what that structure is if one cannot
>> see
>> it all in a feasible JOSM download?
>>
>>
>> _______________________________________________
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>
> Given the size and complexity of major river basins such as the Danube, I would imagine that it would be impossible to map them in much detail without running into this 999-member limit on a relation that tries to include the entire river.
>
> --
> John F. Eldredge -- john at jfeldredge.com
> "Reserve your right to think, for even to think wrongly is better than not to think at all." -- Hypatia of Alexandria
>
>
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