[MapProxy] Limit cache storage up to fixed resolution

[Just van den Broecke]

On 22-06-17 09:59, Oliver Tonnhofer wrote:
> Hi,
>
>> On 22.06.2017, at 08:25, Santiago Horcajo <santiago.horcajo at gmail.com> wrote:
>>
>> Hi, I've got a doubt regarding the solution provided by Oliver.
>
> It's not that difficult to try it out :)
Still todo, aim is somewhere over the weekend.
>
>> If the second cache has a source cache that has a limited grid, how can I go beyond the levels limited by this cache?
>
> It's how a cache in MapProxy works. MapProxy can "request" images from a cache in any size, SRS and BBOX. The cache resamples and reprojects images as necessary.
> This happens when you make a cache available via WMS, or when you use a cache as the source of another cache.
Proof will be in the pudding...:-)
>
>
>> Should I suppose that limited grid cache will give me tiles from the levels that it's not configured to render?
>
> Not directly tiles, but images. The WMTS, TMS and WMS-C service will only provide tiles that are  configured with the grid.
Think I see. So it will not consult the WMS but resample from cache? 
(will monitor what actually happens)

Possibly a future cache option like "resample_from_level/_res" for a 
single full-grid 0-M level cache that:
- stores only levels 0-N
- "blows up" tiles from level N for levels N+1 - M.
- resampling options

Idea is that no WMS is then needed, but may be processing-expensive..
Something like OpenLayers client does with "Layer.serverresolutions" 
(but is unfortunately hardly used, exhausting many caches..). But first 
will try-out Oliver's "2-cache suggestion"...

>
>
> Regards,
> Oliver
>

Best,

--Just

Just van den Broecke
The Netherlands
http://www.justobjects.nl