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

Frederik Ramm frederik at remote.org
Mon Mar 12 07:56:12 GMT 2012


Hi,

    one thing I particularly liked about the now-deceased Tiles at Home 
style was the lowzoom tiles which, in contrast to our rather bland 
Mapnik tiles

http://www.openstreetmap.org/?lat=52.3&lon=7.8&zoom=5&layers=M

or those beefed up by terrain colouring

http://www.openstreetmap.org/?lat=52.3&lon=7.8&zoom=5&layers=Q

actually showed real OpenStreetMap data.

There's nothing keeping one from applying the Tiles at Home lowzoom process 
to a slight variation of our standard Mapnik style however, and out 
comes this (for zoom levels 0-8; from z9 on, the standard Mapnik style 
looks fine):

http://fred.dev.openstreetmap.org/lowzoom/

I guess it's always a question of what audience a map is for, and my 
lowzoom tiles above look funny in areas where landcover has partially 
been imported; but for the mapper to get an idea of where there is data 
and where not, I quite like it. I think that if one applied a little 
more bitmap processing and maybe included, like t at h did, the boundaries 
on the lower zoom renderings, that could be a nice alternative to what 
we have. I'd like to have the roads a bit more prominent against the 
landcover perhaps.

This is just a proof of concept and I'm not updating these tiles at the 
moment, but it would be quite easy to set this up on our main tileserver 
and keep it updated, and it wouldn't use a lot of resources.

(Technical details: Took normal OSM Mapnik style and separated it in one 
style drawing only labels for z0-z8 (transparent background), and 
another style drawing everything but labels on z9; rendered world-wide 
set of no-label tiles on z9; produced z0-z8 tiles by 
bitmap-scaling/compositing appropriate number of z9 tiles and overlaying 
the label-only tile. All sources - hacky, Perl-y - available on request.)

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"



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