[OSM-talk] Missing tiles?

[Jon Burgess]

On Wed, 2008-09-24 at 11:39 -0500, Lukasz Szybalski wrote:
> On Wed, Sep 24, 2008 at 11:24 AM, Joseph Gentle <josephg at gmail.com> wrote:
> > On Thu, Sep 25, 2008 at 2:04 AM, Lukasz Szybalski <szybalski at gmail.com> wrote:
> >> On Wed, Sep 24, 2008 at 10:20 AM, Joseph Gentle <josephg at gmail.com> wrote:
> >> I'm new to the project so if you could give me some shortucts:
> >
> > http://www.google.com.au/search?q=longitude+latitude+of+countries
> >
> >> What would be estimated size for min0 max 17?
> >> ...
> >
> > The whole world from 0 - 17 is about 20 billion tiles. If you chop out
> > the oceans, the arctic and antarctica you might have ~5 billion tiles
> > to render. Zoom google maps all the way out and look at proportional
> > sizes of the countries on that map for relative sizes.
> >
> > If you don't use appropriate storage for the tiles, each tile will
> > take up at least 4KB. Unless you're clever 5 billion tiles will take
> > at least 20TB to store.
> 
> ok That is a little too much considering I can buy 500gb drive for
> $70, so storage is max 500, now 50gb I can spare.
> 
> What would be a bbox for:
> http://maps.google.com/?ie=UTF8&ll=37.0625,-95.677068&spn=36.231745,92.109375&t=h&z=4
> 
> bbox=(37.0625,-95,36.23,92.10)
> 
> Is google zoom reasonably close or same as in mapnik? From google it
> would seem zoom max 15 should be enough for what I need.

The number of tiles drops by a factor of 4 for each zoom so the above
estimate becomes about ~1TB for all up to z15 and take something in the
order of a month of CPU time.

mod_tile not only servers the tiles but also ensures they are cached and
rendered in real time when required. This avoids the need to pre-render
tiles in many cases.

	Jon