[Talk-ca] Islands with coastlines not showing up in OSM

Adam Martin s.adam.martin at gmail.com
Wed Feb 24 18:08:20 UTC 2016

Hey Denis,

Changes to the coastline takes time to pass through the tile rendering. If
I recall correctly, the coastal tiles may take several weeks to update and
require manual intervention. Looking at the Wiki, I see this (
http://wiki.openstreetmap.org/wiki/Coastline): "*Coastline rendering in
Standard tile layer
<http://wiki.openstreetmap.org/wiki/Standard_tile_layer> may update later
than other rendering changes. To avoid major disruptions of map rendering
due to data errors the coastline is not automatically updated if there are
larger changes in the geometry compared to the last time it was
successfully processed. For example any addition or removal of a lake with
coastline tag will require manual intervention.*"

The same page also notes that "*At low zoom levels (used for z0-9), up to
and including zoom level 9, Mapnik
<http://wiki.openstreetmap.org/wiki/Mapnik> renders all the sea as a solid
fill of blue, generated from the shapefile
which has a relatively low resolution. At higher zoom levels the coast
polygons used are generated from a larger shapefile
<http://data.openstreetmapdata.com/land-polygons-split-3857.zip>) which are
automatically generated almost daily from planet dumps + diffs (note: if
you edit the coastline then you have to be patient for the result of the
changes to render at the higher zoom levels).*" If your changes are very
recent, it may not be showing up as the tiles have not been rendered. If
they are older, check to make sure that the polygons are closed loops so
that the renderer knows what to do with them.


On Wed, Feb 24, 2016 at 2:27 PM, Denis Carriere <carriere.denis at gmail.com>

> Quick question for anyone on this mailing list.
> We are having issues displaying islands up in northern Canada, some
> islands are showing up correctly and some do not.
> We seem to have all the tagging correct and the correct geometry
> (validated with JOSM the coastline so it's not reversed).
> Any reason why it's not showing up properly in OSM? Is there a delay of
> 24+ hours for any features that are related to the coastline?
> Here is one of many features that are not getting rendered:
> *Thomas Work Island, Nunavut (Not showing up)*
> https://www.openstreetmap.org/way/398936588
> *OSM Tags*
> name=Thomas Work Island
> natural=coastline
> place=island
> source=NRCan-CanVec-10.0
> Any ideas anyone?
> *~~~~~~*
> *Denis Carriere*
> *GIS Project Manager*
> *Twitter: @DenisCarriere <https://twitter.com/DenisCarriere/>*
> *OSM: DenisCarriere <https://www.openstreetmap.org/user/DenisCarriere>*
> GitHub: DenisCarriere <https://github.com/DenisCarriere>
> Email: Carriere.Denis at gmail.com
> _______________________________________________
> Talk-ca mailing list
> Talk-ca at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk-ca
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