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When I try to download this polygon I get this error;

Error while generating polygon. You could check the geometry through an analyser:

analyser using an internal database. analyser using OSM API (slower). Message from postgresql server: NOTICE: missing connexion at point -3.9528684f 52.9621599f - ways: 4685489 NOTICE: missing connexion at point -3.9471549f 52.9622537f - ways: 4685491 NOTICE: missing connexion at point -3.8930782f 53.2573835f - ways: 50894166 208237990 98747616 50894167

I'm new to OSM does anyone know how to fix it.

asked 19 Oct '14, 20:01

Malpas%20wanderer's gravatar image

Malpas wanderer
accept rate: 0%

What software is it that is giving you the "Error while generating polygon"?

(19 Oct '14, 20:50) SomeoneElse ♦

Obviously you're getting these error messages from :

alt text

Strange enough that the analysis tool on this page fails to provide a useful error message:

As this is a server maintained by the French OSM community, I'd recommend to create a ticket on the issue tracker - However, I'm not quite sure which area is the right one. Maybe you want to check on a French list/forum?

In any case, if you're using this page to download some GeoJSON/etc. format, you might as well consider Overpass Turbo: - Just hit the "Run" + "Export" buttons for various output formats.

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answered 19 Oct '14, 21:50

mmd's gravatar image

accept rate: 37%

edited 19 Oct '14, 22:10


Many thanks for that. After some experimentation exporting as a KML file seems to have been imported to my application satisfactorily.

(20 Oct '14, 00:15) Malpas wanderer

The Snowdonia NP relation appears to be fine according to Relation Analyser (see

In general its worth checking with OSM Inspector for the state of large polygons & relations before trying to download them. OSM Inspector reports and error but I couldn't find the break in the ring.

If something is broken then it's usually best to badger someone with experience of fixing them rather than trying to get to grips both with multipolygons and finding the tools which are most useful in the situation. Normally I would pull down the relation into JOSM and use JOSM to find and fix the issues.

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answered 19 Oct '14, 23:39

SK53's gravatar image

SK53 ♦
accept rate: 22%


The solution in the previous post has seemed to work for me so I'm happy.

many thanks for offering your advice too though.

(20 Oct '14, 00:18) Malpas wanderer

Yes, but the ideas of these Q&As is to offer advice which might be helpful to others too.

(20 Oct '14, 15:02) SK53 ♦

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question asked: 19 Oct '14, 20:01

question was seen: 2,086 times

last updated: 20 Oct '14, 15:02

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