Lake Kyoga in Uganda is not rendering in OSM, at first glance you may think it was deleted but on the checking, the data is actually still there. The tags look okay, but it is not rendering, what could be the problem.

~Geoffrey

asked 17 Aug '18, 07:18

Kateregga1's gravatar image

Kateregga1
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edited 18 Aug '18, 19:23

aseerel4c26's gravatar image

aseerel4c26 ♦
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(17 Aug '18, 20:13) andy mackey
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@andy mackey: Your link is missing the details.

(17 Aug '18, 21:06) aseerel4c26 ♦
2

I've added the link in a full answer, because this is probably the first of many formerly rendered polygons which now need to be prioritised for fixing.

(18 Aug '18, 12:56) SK53 ♦

Thank you @Alecs01 for fixing the problem, the lake is now back and rending in OSM. Thanks @nevw and @SK53 for sharing the tools that we can use to easily identify other issues in the data.

(18 Aug '18, 13:33) Kateregga1
1

Thanks aserel4c26 and SK53 that is the diary link i had intended to point to.

(18 Aug '18, 17:23) andy mackey

There was a self-intersecting way around here: https://www.openstreetmap.org/relation/326665#map=15/1.6737/33.1966 it should be ok now.

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answered 17 Aug '18, 08:32

Alecs01's gravatar image

Alecs01
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Recent changes on the main rendering servers now mean that the software used to construct polygons & ways (osm2pgsql) no longer tries to fix problems such as the self-intersection in the outline of this lake. This is just one example of many polygons (and, less likely, linear features) which will no longer be rendered on the Standard Carto-OSM layer. In the short term this will mean things disappearing from the map, but in the longer term this is expected to result in much better quality data for data consumers because issues will be fixed at source in OSM.

Christoph Hormann (Imagico) has written a good description of the changes and their rationale here: https://www.openstreetmap.org/user/imagico/diary/44711

As @nevw says in their answer, use of data quality tools such as OSM Inspector, Osmose etc., can rapidly identify these problems. I wrote a blog post long ago about using the first of these for this purpose.

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answered 18 Aug '18, 12:55

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SK53 ♦
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edited 18 Aug '18, 13:00

The Osmi tool can check for such errors
https://tools.geofabrik.de/osmi/?view=areas&lon=32.86198&lat=1.48669&zoom=9
Once fixed it may take a few days to re-render at all zoom levels.

There also a couple of relation analizers to help find such errors
https://wiki.openstreetmap.org/wiki/Relation_Check

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answered 17 Aug '18, 08:41

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nevw
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edited 17 Aug '18, 08:44

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question asked: 17 Aug '18, 07:18

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last updated: 18 Aug '18, 19:23

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