[Tilecache] Re: MetaTiling - does projection affect?

[christopher.schmidt at nokia.com]

> 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.

Is this related to the above thread? I don't understand; lack of locking 
and adding a feature to TileCache seem unrelated to me.

> 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 don't understand why this would be the case; I mean, the feature you 
wrote isn't solved by a patch that exists in TileCache, so if you want
that feature, you'll need to write a patch.

However, it shouldn't go in the Cache. It should be a Layer option;
missingTile=/path/to/file.png or some such, and then at the layer level,
we can read that when an empty tile is found and return that instead.

A brief look suggests that Layer.render might be the right place to add
such a check.

-- Chris