[Tiling] Fwd: [OSGeo-Standards] Irregular tile coverage in TMS?

[Oliver Tonnhofer]

Hi,

I think we need to differentiate between active and passive TMS implementations. When a tile is missing for an active implementation, it often means a cache-miss (unless the server knows more about the coverage) and the tile needs to be created. For passive implementations, i.e. bunch of static files, there is no way to create that tile. 

On 13.09.2010, at 04:12, Matt Priour wrote:
> I think requiring servers to actually cache individual empty images for each empty tile is not useful.

Well, that's an implementation detail. MapProxy can store symbolic links for all tiles that only contain one color (empty, water, forest, etc.). So you don't waste space, only inodes.

> The server response, whether it is an no data image for each request, a redirect to a common no data image, or a simple 404; is not really all that important either. Clients should be able to handle any of those type responses and behave appropriately.


Yeah, I agree with you, clients should be prepared to get different replies. But I would like to suggest that returning empty images should be 'best practice'.

Regards,
Oliver