[OSM-dev] render_expired for zoom 19 and metatiles

[M∡rtin Koppenhoefer]

2011/1/16 Jon Burgess <jburgess777 at gmail.com>:
> It is relatively easy to extend the current scheme to support more zoom
> levels but we need to avoid breaking the existing setups which have
> millions of tiles cached with the current directory layout. One simple
> fix would be to extend to a 6 byte layout for zoom 21-24, 7 bytes for
> zoom 25-28 etc.


Probably there will be few practical value of extending the scheme for
zoom levels higher then 24: in zoom 24 one pixel corresponds to
roughly 9 mm (tilelength around 2.4 m), hence reaching the accuracy
limit of the OSM database coordinate scheme.

cheers,
Martin