[Tilecache] Quick panning with overlays

[Josh Livni]

Yves,
I think 20 overlays is .. a lot.  especially from a dynamic WMS - must take
a while to render, forget panning!  Instead of grouping them in OpenLayers
(which would still mean 20 OL layers), can you group them in the WMS -- that
helps with things like labeling as well..

As for caching, I assume something like TileCache was meant.  I think I
actually saw a patch to tilecache recently that lets you do a form of
'cascaded wms' (eg merging of wms layers) in tilecache itself for that
matter...

  -Josh

On Wed, Nov 26, 2008 at 6:37 AM, Yves Moisan <yves.moisan at boreal-is.com>wrote:

>
> > maybe the right question would be: And how many overlay layers do you
> > have Yves?
> >
> > I remember one OL user was complaining about speed, and he had like 80
> > layers :D Keeping it under 3 layers at a time should do the trick i
> > think.
>
> Well indeed that's an issue.  I have 20 some overlays.  I know it's too
> much and a lot of those layers could be turned into composite layers
> e.g. all line feeatures could be grouped in one layer with symbology,
> but that means using a custom LayerSwitcher.
>
> > People should take more care with number of layers. Instead of
> > piling up the layers, one should group layers in wms request: you
> > loose some speed on rendering it, but if you use caching its well
> > worth it ;)
>
> The overlays are not cached.  I'm supposed to have a script that bundles
> calls to MapServer somewhere.  If you have pointers, I'll take them.
>
> Thanx,
>
> Yves
>
>
>
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