[talk-ph] Fwd: Mapnik coastline shapefile update - Philippine coast still somewhat square when exported

D Tucny d at tucny.com
Tue Mar 3 05:44:15 GMT 2009


FYI...

Just sent this to osm-talk...

The coastline shapefiles used by the mapnik layer have been updated and the
coastline at zoom 10 and above looks OK now, but, it seems that for lower
zoom levels, it's still broken... Hopefully Jon can fix it :)

d

---------- Forwarded message ----------
From: D Tucny <d at tucny.com>
Date: 2009/3/3
Subject: Mapnik coastline shapefile update - Philippine coast still somewhat
square when exported
To: Jon Burgess <jburgess777 at googlemail.com>
Cc: OSM Talk <talk at openstreetmap.org>


2009/3/3 Jon Burgess <jburgess777 at googlemail.com>

> On Mon, 2009-03-02 at 10:51 +0000, Kevin Peat wrote:
> > I made some changes a couple of weeks ago to the banks of the River
> > Dart
> > through Totnes
> >
> >
> http://www.openstreetmap.org/?lat=50.42863&lon=-3.67974&zoom=15&layers=B000FFF
> >
> > Obviously those changes have been picked up as the county boundary is
> > rendering along the updated river bank but the actual river isn't.
> >
> > Is this just a time lag thing or have I done something wrong?
>
> There is a lag. The coastlines are generated from a set of shapefiles
> which is periodically updated from the OSM data. I've just fetched the
> latest updates.
>
> You probably won't see much difference in the map tiles until the
> weekend, but images from the export tab will show them right away (see
> attached).
>

There's a large chunk of bad coastline around The Philippines that's been
there since some shapefile update in the recent past...

It can be seen here...
http://www.openstreetmap.org/?lat=15.481&lon=120.274&zoom=9&layers=B000FTFT

The coastline is all OK now (there were a couple of problems at one point)
and the view at the coastline checker (
http://tile.openstreetmap.nl/coastlines.html?lat=15.481&lon=120.274&zoom=9)
and a local mapnik render I've done using the coastline checker output both
show the coastline correctly...

A trac ticket was raised about this problem a couple of days ago now, but,
I'd have expected an update of the shapefiles to have corrected this... It
looks like it's only corrected the problem above zoom level 10 though
suggesting that only the processed_p shapefiles have been updated...

So... some questions...
Is there a problem with the world boundaries shapefiles being used? Were
they generated from the processed_p shapefiles at some point? Are the world
boundaries files used on tile different to the ones packaged here
http://tile.openstreetmap.org/world_boundaries-spherical.tgz? What would be
involved in regenerating them? Once regenerated, could new ones be made
available somewhere?

Thanks,

d
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