[Tilecache] Quick panning with overlays

[Christopher Schmidt]

On Tue, Nov 25, 2008 at 04:47:19PM -0500, Yves Moisan wrote:
> Hi All,

As you've described it, this sounds like an OpenLayers question, not a
TileCache question.

That said, I'm not sure why you say overlays 'slow things down' --
perhaps you're not using a different set of DNS hostnames for your
overlays? If so, do that -- they will then load completely in parallel
to your baselayers. (Also, I hope you're using the multiple-DNS trick,
as that will cause a much faster visible loading time to the user...) 

> I'm still amazed at TC on mod_python :-).  However there is a bit of a
> show stopper in that panning is slowed down by the extra WMS requests
> made for the overlays.  I was thinking maybe I should give my users a
> "unselect all overlays" button so they could pan more quickly in the
> image without having to wait for the overlays to be rendered, but then
> that means I have to remember which overlays were on so I can "reselect
> all overlays" again.  
> 
> Of course that means that as a user you need to know when you'll be in
> sufficiently crazy panning mode to justify unselecting all overlays to
> get the speed boost, or maybe you'll just zoom out a couple of levels
> and zoom back in ??  I wonder what people do when overlays slow things
> down ?
> 
> Cheers,
> 
> Yves
> 
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-- 
Christopher Schmidt
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