[OSM-talk] Coastline updates

Jon Burgess jburgess777 at gmail.com
Fri Feb 25 19:31:55 GMT 2011

On Fri, 2011-02-25 at 20:01 +0100, Jochen Topf wrote:
> Hi!
> Falmouth:
> http://www.openstreetmap.org/?lat=50.15364&lon=-5.0639&zoom=17&layers=M
> Looks ok now in this zoom level. Still some errors if you zoom in.
> I had a look at it again and marked some tile manually as dirty and I
> get the
> correct rendering then. So the problem seems not to be the coastline
> stuff
> but that there are tiles that haven't been re-rendered for half a
> year!?

I updated the coastline shapefiles used by the mapnik layer last night.
The previous update was about 4 weeks ago.

If no one edits any data in an area after the coastline shapefiles are
changed then it may be a long time before the tiles are rendered again
to pick up the changes (as you are seeing here).

Normally I force the zoom 0 - 12 tiles to re-render across the world
each time I update the coastline shapefiles but it takes too long to do
all zoom levels on each update. 

Back in January I ran a process to re-rendered all tiles last rendered
prior to 1st Oct 2010 across the full 0-18 zoom range. This took a few
weeks to complete and should have picked you older changes. I will
consider running it again with a more recent cut-off point.

Perhaps some of the other discrepancies are due to newer edits to the


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