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How to detect flooding source (e.g. coastline mistake)?

2

In the past month, I've seen repeated water-flooding that keeps flipping between flooded/not flooded. This means that map is rendered inconsistently, as seen below. half-flooded map - screenshot of https://www.openstreetmap.org/query?lat=50.06402&lon=14.47634#map=19/50.06396/14.47586

Yet, according to tile status, tiles are clean and rendered at the same time: https://tile.openstreetmap.org/19/283225/177664.png/status is a northernmost flooded tile, and https://tile.openstreetmap.org/19/283225/177663.png/status is one non-flooded just adjacent.

Querying for enclosing features doesn't give any hints as to where the water comes from. Judging from the [flood] questions, this seems to be a coastline error, but as I'm in mainland Europe, the coastline is a bit long for manual inspection. Looking at OSMi Coastline view, I don't see any issues either; and from http://tile.openstreetmap.org/cgi-bin/debug, I see coastline edits a few days old.

Now, my issue isn't "someone fix this instance of the error" (which is not entirely polite, given that I should theoretically be capable of fixing it myself) but rather "how can I find where the error is to fix this"?

asked 30 May '17, 11:02

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Piskvor
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edited 30 May '17, 11:24

1

Given the location I would consider a coastline issue rather unlikely (not that it couldn't happen, but then there would have been lots of other complaints from all of Europe). Are you sure that you are not looking far to far and that nobody simply messed up the local riverbank?

(30 May '17, 11:43) SimonPoole ♦

Hmm, that looks plausible. Will check, thank you.

(30 May '17, 12:03) Piskvor
1

Hmm...no idea what caused it, but seems to be fixed. There have been complaints in neighboring countries, so perhaps it could have been a major riverbank.

(13 Jun '17, 09:52) Piskvor

Source code available on GitHub .