[MapServer-users] How to avoid writing empty tiles with mapcache_seed

[Philippe Ghesquiere]

Hi Johannes,

Your hint sounds like a good workaround.
I'll apply it if there is no direct parameter in mapcache.

Thanks
Philippe

On Thu, Mar 26, 2026 at 9:26 AM Johannes Paul <johannespaul92 at gmail.com>
wrote:

> Hi Philippe,
> by using <detect_blank/> you can store a quadruplet of the rgba color in
> the data blob instead of the compressed image data, it should then be easy
> to get rid of these tiles in the SQLite if needed (DELETE FROM tiles WHERE
> length(tile_data) = 4;).
> https://mapserver.org/mapcache/caches.html#blank-tile-detection
> Johannes
>
> On Thu, 26 Mar 2026 at 08:49, Philippe Ghesquiere via MapServer-users <
> mapserver-users at lists.osgeo.org> wrote:
>
>>
>> Hi all,
>>
>> While creating a GPKG cache with mapcache_seed, I would like to avoid
>> writing empty tiles.
>> I know that <symlink/> can save disk space. But I would like to get rid
>> of these empty tiles.
>> Is there any parameter to achieve it ?
>>
>> If there is no such parameter, do you have any idea for some post-process
>> SQLITE command to remove these tiles ?
>>
>> Thanks for your help
>> Philippe
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