[OSM-dev] Rendering differences between own installation of mod_tile+mapnik vs. *.tile.openstreetmap.org

Jon Burgess jburgess777 at googlemail.com
Thu Jan 8 21:44:54 GMT 2009


On Thu, 2009-01-08 at 14:08 +0200, Ilkka Kaakkola wrote:
> My setup is using data downloaded recently (osm.xml , mapnik,  
> world_boundaries, processed_p, Planet.osm) and osm.xml has not been  
> customized for the first two example images (other than paths &  
> database logins). Files have been downloaded from the places
> described  
> at http://wiki.openstreetmap.org/index.php/Mapnik
> 
> 
> Why is my version of the map lacking lots of detail (the big lake,  
> coastline detail, scattered little bodies of water) that is visible
> in  
> the osm generated image?
> 
> http://xe.nic.fi/~xenic/tile_problem.png
> 

The coastline shapefile used for low zooms on the tile.openstreetmap.org
server is generated using the coastcheck[1] utility with the following
parameters:

#define RESOLUTION 100
#define TILE_OVERLAP  20000
#define MAX_SEGS  200

This generates a set of shapefiles which I then run through PostGIS to
simplify the geometries:

$ shp2pgsql -s 900913 -g way processed_p shoreline_a | psql -q gis
$ pgsql2shp -f shoreline_300 gis "select simplify(way, 300) as the_geom,
gid as id from shoreline_a where area(simplify(way,300)) > 0"

I have made the current set available at [2].
The latest osm.xml with tweaks to use these shapefiles is at [3].

	Jon



1: http://trac.openstreetmap.org/browser/applications/utils/coastcheck
2: http://tile.openstreetmap.org/shoreline_300.tar.bz2
3: http://tile.openstreetmap.org/osm.xml







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