[OSM-talk] Mapnik Lowzoom TIles - proof of concept

[Christian Quest]

Based on Frederik lowzoom idea, I started improving the low zooms on
our OSM-FR style...

Here is zoom 7 (others are in the render_list queue):
http://tile.openstreetmap.fr/?zoom=7&lat=46.88069&lon=3.13697&layers=0000B0FFF

Here is how I did it:
- modify my OSM-FR to remove all labels and boundary at zoom 8 (which
was already using landcover/landuse),
- generate 4 large PNG using nik2img
- combine them and generate one large tiled z8.tif using
gdal_translate (133MB, if you want to play with it I can share the
result)
- create a very simple stylesheet to test using this z8.tif as raster,
then add placenames and boundaries

It's a work in progress. I'm currently merging this lowzoom stylesheet
to my main OSM-FR style sheet.

I've not played with imagemagick, it is just a lanczos downscaling
made by mapnik.

Label ordering is handled by using the place=* tag, then the
population=* tag so large cities are placed first.
The placename density is limited using text-min-distance.

-- 
Christian Quest - OpenStreetMap France
Un nouveau serveur pour OSM... http://donate.osm.org/server2013/