[Talk-ko] Broken (multi)polygons in Korea

[Max]

Quite difficult i must say.

http://maproulette.org/map/2420/2050730
Just to say that the riverbed is mapped in a detail that is useless 
because it represents the waterlevel and riverbed at the time of the 
satellite image. There are so many occlusions and little islands, it's 
almost easier to start over.

The outer riverbank has now 5 outer relations, not sure if this is 
supposed to be like that.

I used JOSM to merge the overlapping polygons and then ID rying to fix 
the islands that disappeared in the process.

I think I better leave this kind of stuff to others.


On 2017년 03월 19일 14:46, Jochen Topf wrote:
> Thanks, Andrew!
>
> in my newest batch of Maproulette challenges, I have included a special
> challenge for Korea, because there were so many problems there.
>
> I encourage everbody to help:
> http://area.jochentopf.com/fixing.html#duplicate-segments-in-closed-ways
>
> Jochen
>
> On Sun, Mar 19, 2017 at 10:02:57PM +0900, Andrew Errington wrote:
>> Date: Sun, 19 Mar 2017 22:02:57 +0900
>> From: Andrew Errington <erringtona at gmail.com>
>> To: OpenStreetMap Korea <talk-ko at openstreetmap.org>
>> Subject: Re: [Talk-ko] Broken (multi)polygons in Korea
>>
>> Ok.  I contacted who I thought was the most prolific mapper of forest
>> outlines.  They said they did it as quickly as possible because it was
>> important for Koreans to see forested areas on the map.  Now they are
>> reviewing and improving those polygons.
>>
>> Best wishes,
>>
>> Andrew
>>
>> On Mar 15, 2017 5:24 PM, "Andrew Errington" <erringtona at gmail.com> wrote:
>>
>> As far as I know there has been no import of forest area data.  There is a
>> prolific mapper who has made rough outlines of forested areas.  Some of
>> these areas overlap with others.  Some areas intersect with themselves.  I
>> don't think each area represents anything "on the ground", just a
>> convenient chunk to draw a line around.
>>
>> I will contact that mapper and ask about his or her methodology.  There are
>> other "large area mappers" too.
>>
>> Best wishes,
>>
>> Andrew
>>
>> On Mar 15, 2017 4:58 PM, "Jochen Topf" <jochen at remote.org> wrote:
>>
>> Hi!
>>
>> there are quite a lot of broken (multi)polygons in the OSM data. I have
>> started an effort to clean them up. You can find out more at
>> http://area.jochentopf.com
>>
>> I found that there are many problems with self-intersections in South
>> Korea, often on forests. You can see this here:
>> http://tools.geofabrik.de/osmi/?view=areas&lon=128.02487&lat=36.21680&zoom=8
>>
>> Was there some kind of import? Can you, the Korean community, help with
>> fixing them? How good is that forest data anyway? Is it worth cleaning
>> up? I'd appreciate any information and help.
>>
>> If you are interested, I can also create special Maproulette challenges
>> or create special data extracts or so to help the Korean community clean
>> this up?
>>
>> Jochen
>> --
>> Jochen Topf  jochen at remote.org  https://www.jochentopf.com/
>> +49-351-31778688
>>
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