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I have edited a part of the coastline. The tags look good to me but the Mapnik map still uses the old coastline. Is there something else to do?

asked 16 Jul '10, 22:40

ChrisH's gravatar image

accept rate: 15%

edited 04 Jul '11, 16:50

katpatuka's gravatar image



Does the same timing apply to railway lines modifications, before one can see them in the main map?

(28 Apr '11, 07:53) averageman

No. coastlines are a special case. Other features render in the usual time frame, so if they don't appear within a day, check that your browser cache has been refreshed and then check that your tags don't have any errors.

(28 Apr '11, 15:03) ChrisH

As explained on the OSM Wiki, the coastlines used by the main Mapnik map come from shapefiles which are generated every few weeks. This means you will have to wait a while for your changes to become visible.

The reason for this is that building the landmass polygons from coastlines is a relatively complex operation, and tile rendering performance would degrade massively if one would attempt to do this "on the fly" when tiles are rendered.

If you want to find out when the coastline was last processed, check the time stamp on the file file, for example by typing, on a Linux system,

wget --server-response --spider

Then check the Last-Modified header in the response:

HTTP/1.0 200 OK
Date: Fri, 15 Oct 2010 17:27:52 GMT
Server: Apache/2.2.8 (Ubuntu)
***Last-Modified: Fri, 24 Sep 2010 23:44:09 GMT***
ETag: "2ae2f4-2f4e0e1-49109f476c440"
Accept-Ranges: bytes
Content-Length: 49602785
Content-Type: application/x-bzip2

Note that even after the coastline has been processed into a shape file, that will only show up on the map when the relevant tiles have been re-rendered.

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answered 16 Jul '10, 22:52

Frederik%20Ramm's gravatar image

Frederik Ramm ♦
accept rate: 23%

edited 05 Feb '11, 00:02

Well Frederik, when I asked this question four months ago,

you directed me to this answer. Problem is, my coastline edits have still not shown up at any zoom level.

At what point should we begin to suspect a problem causing tiles to take an inordinately long time to re-render?

(14 Jul '13, 01:36) gpspilot1

@gpspilot1: Simply looking up the last modified date of the coast line (with the command Frederik suggests) results in: "Last-Modified: Thu, 07 Feb 2013". The last coast line update was on 7th February 2013. Same day for the processed_p.tar.bz2 which is used for higher zoom levels according to the wiki page.

(14 Jul '13, 03:22) aseerel4c26 ♦

This is a frequently repeated question. Unfortunately, the referred answers are several years old and this may slightly be confusing. What we/I know today is that the vector Planet_land/_sea, scale/zoom levels, (none-trivial)tiles generation and the change detection could be done in several hours. But what we/I don't know is how to help, even if we/I want to help. Thanks!

(14 Jul '13, 07:40) sanser

Updates are now daily.

(24 Sep '13, 20:07) Firefishy ♦♦

Note also that on the highest zoom levels the new coastline may show up only months later. You can see an example of this (at least as of writing this) at vs. -- The zoom level 18 still doesn't show my editing of the coastline even though it's been nearly half a year from editing and I've viewed the location (with zoom 18) a number of times after (which to my understanding is sometimes needed for new tiles to be created).

Maybe someone can clarify this but it really can take months for the higher level modifications to render.


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answered 28 Apr '11, 01:44

jaakkoh's gravatar image

accept rate: 0%

Coastlines are now updated daily.

Check to see when the file (coastlines) was last updated.

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This answer is marked "community wiki".

answered 24 Sep '13, 20:06

Firefishy's gravatar image

Firefishy ♦♦
accept rate: 29%

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question asked: 16 Jul '10, 22:40

question was seen: 19,631 times

last updated: 24 Sep '13, 20:07

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