[OSM-dev] Blank Tiles at z23 and Deeper

[jpk]

On Tue, Oct 9, 2012 at 10:21 AM, Frederik Ramm <frederik at remote.org> wrote:
> Hi,
>
> On Tue, 9 Oct 2012 00:21:25 -0400
> jpk <_ at jpk.is> wrote:
>> In any case, I set up my tile server for
>> this purpose.  I changed the #define MAX_ZOOM to 30 in mod_tile's
>> render_config.h, and set MAXZOOM in renderd.conf to 30.  That's enough
>> to get the tile server to serve tiles down to z30 instead of 404'ing.
>
> But the directory structure used to store the metatiles supports only 20
> bits for x and y, so i would expect that on z21 and above you'll not be
> able to retrieve tiles from your server (or maybe see the same tile
> not matter what coordinates you use)... or are you using someting other
> than mod_tile?
>
> Bye
> Frederik
>
>
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I am indeed using mod_tile (r28702).

Here's what I'm seeing at z17, 19, 20, 21, 22, and 23.  So you can see
21 and 22 are working.  All tiles at zoom levels 23 and greater,
though, are that solid green-ish color.
http://imgur.com/a/qCXAx#0

Although, you may be on to something.  Can you elaborate on "the
directory structure used to store the metatiles supports only 20 bits
for x and y"?  I see in /var/lib/mod_tile there are directories that
look like the correspond to zoom levles, but stuff that doesn't look
like x/y directories (like if you generate some tiles with gdal2tiles
or a similar tool). The mod_tile README talks a little bit about the
directory structure, and the limitations of using the z/x/y.png
structure, but I'm still not sure what's going on there and what would
break at higher zoom levels.

Thanks!
jpk

-- 
john p. kiffmeyer