[OSM-talk] Mapnik coastline shapefile update - Philippine coast still somewhat square when exported

[D Tucny]

2009/3/5 Jon Burgess <jburgess777 at googlemail.com>

> On Tue, 2009-03-03 at 13:41 +0800, D Tucny wrote:
>
>
> > There's a large chunk of bad coastline around The Philippines that's
> > been there since some shapefile update in the recent past...
>
> I only updated the low zoom shapefiles last time. I just pushed an
> updated set of low zoom ones too but that won't start rendering until
> the weekly mapnik import finishes in a few hours.
>
> > 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...
>
> OK, we'll see how things turn out tomorrow.
>
> > 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...
>
> Yes
>
> > So... some questions...
> > Is there a problem with the world boundaries shapefiles being used?
>
> No
>
> > Were they generated from the processed_p shapefiles at some point?
>
> They were derived from vmap0 data and we are slowly replacing them with
> data derived solely from the planet.osm file.
>
> I have just committed the changes into the mapnik osm.xml files so you
> can see how they are used, I was holding back because there were some
> occasional rendering issues, but I think these are resolved now.
>
> >  Are the world boundaries files used on tile different to the ones
> > packaged here
> > http://tile.openstreetmap.org/world_boundaries-spherical.tgz?
>
> The ones on the live map are different.
>
> > What would be involved in regenerating them? Once regenerated, could
> > new ones be made available somewhere?
>
> http://tile.openstreetmap.org/shoreline_300.tar.bz2
>
> They are generated using the same coastcheck utility as is used for
> processed_p but with some slightly different parameters and some data
> simplification. The details are in:
>
> http://lists.openstreetmap.org/pipermail/dev/2009-January/013485.html
>
> Since I wrote that email I found that the RESOLUTION setting caused some
> issues, the current values I use are:
>
> #define RESOLUTION  0
> #define TILE_OVERLAP  20000
> #define MAX_SEGS  200
>

That's great, thank you very much both for fixing the problem and for your
detailed response... I'd somehow missed the mail from January...

Thanks,

d
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