[Tilecache] Re: MetaTiling - does projection affect?

[Mark Deneen]

On 5/6/2010 7:27 AM, christopher.schmidt at nokia.com wrote:
>
> Er... to quote The Doctor: 'what? What?!'?
>
> This is completely untrue. TileCache is designed to support having metaTiling on during production use. The reported behavior is confusing to me, and I don't understand it, but that doesn't mean that metaTiling is not designed for production use. In fact, for many types of access, turning on metaTiling in production is all that allows it to work; with very slow servers, you prevent OpenLayers from 'swamping' an external server (by sending many requests at once) because TileCache performs local locking to prevent re-requesting the same area multiple times.
>   

> So, in short:
>  1. metaTile in production: good
>  2. TileCache 2.10: bad (and all releases back to 2.03, I think.)
>  3. Easy to patch
>  4. New release relatively soon
>  5. Tile numbers seem reasonable
>
> -- Chris_______________________________________________
>
>   

Chris,

Would you be interested in a patch to the DiskCache which makes it so
that TileCache will not cache any more tiles, other than what is in the
existing cache?  If a tile is missing, the DiskCache will return a
configurable default tile image.

We use this so that we can seed the whole world, and many levels of
North America.  Then, if a user tries to zoom in to an area which we
don't have tiles for, they just get a default tile image.

Unfortunately, now that I see your message, I wrote this patch because
of the behavior I saw without the patch to 2.10.

I have other changes to my DiskCache as well, so I'd have to separate
them before I could send it to you.  My disk cache calls a function
every time a tile is added to the cache -- the file name is inserted
into a queue and another process runs in the background which optimizes
the .png files.  I could make this configurable as well, but we're
stretching my knowledge of python and dynamic invocation.

Mark