[OSM-dev] How to delete metatiles?

[Frederik Ramm]

Hi,

Stephan Knauss wrote:
> On 16.01.2011 20:11, Jon Burgess wrote:
>> Does anyone use the existing scheme with max_zoom>  18? If not the
>> changes could only effect higher zooms, perhaps as a compatibility mode.
> 
> I do with zoom 19. And until a few minutes ago I felt fine doing it.
> Now I feel confused.

The existing scheme *can* be used up to zoom 20, but that's how far it 
goes (because we only have 5 * 4 = 20 bits of coordinate space available 
for x and y).

If we wanted to introduce a new scheme that went past this limit, e.g. 
by adding an extra hierarchy level, then this would most likely not be 
backwards compatible; i.e. if Jon wanted to support the new scheme on 
tile.osm.org he'd probably have to move huge numbers of tiles to their 
new directories.

So one could think of a hack where for tiles up to zoom level "x" the 
current scheme was used, and for everything higher than "x" the new 
scheme would come into play.

Had it turned out that nobody uses zoom levels > 18, then it would havew 
been easy to define x=18, and implement a new scheme that comes into 
play for tiles on zoom levels 19+.

Bye
Frederik

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