[OSM-talk] osmarender slippy map rendering

[Lars Aronsson]

80n wrote:

> This is an intentional style.  As you zoom in place-names get 
> bigger but also become semi-transparent.  At some level they 
> become invisible, ideally when the extent of the place is larger 
> than the viewport.

I like this, but there are two things to wish for:

1. The current definition of a place=city is one with more than 
100,000 inhabitants.  This Malmö, Helsinki, Cambridge, Oxford and 
a lot of places.  But we should need another level for places 
bigger than 1 million inhabitants like Copenhagen, Riga, London 
and Berlin.  The current city names look small for these places.

2. Tiles at home renders place=city as grey text at zoom=12, which 
means it should be black at zoom=11.  But t at h doesn't go that far.  
Instead, zoom=11 is created by lowzoom.pl by scaling down the 
zoom=12 image.  The result is that at zoom=11, =10 and =9 you see 
the town names (population 10,000 - 100,000) a lot better than 
city names.

In combination, these wishes suggest that a place=megacity should 
be printed with a very large font, spanning very many tiles.  
This is of course problematic with respect to performance.  
Changing the megacity name would cause many tiles to be rendered.  
And rendering one tile would require a search of a large 
neighborhood (outside the current tile) for any megacities, parts 
of the names of which could touch this tile.  Rendering megacity 
names would also only affect zoom levels 7--11, which today aren't 
covered by the proper tiles at home, but by lowzoom.pl.  But perhaps 
a list of megacities (there really aren't that many in this world) 
could be extracted from the weekly planet.osm and supplied in svn 
as part of lowzoom.pl ?

By the way, how are place=country names treated today?


-- 
  Lars Aronsson (lars at aronsson.se)
  Aronsson Datateknik - http://aronsson.se