RfD: Support for layer specific resources

[Martin Schulze]

Bernhard Reiter wrote:
> On Thu, Apr 15, 2004 at 08:20:50PM +0200, Martin Schulze wrote:
> > In the past, Thuban supported mostly local layers.  As a result,
> > several dialogs were not classified layer-specific and hence
> > controlled through a general control within Thuban.  This poses a
> > problem since the general control of Thuban which also creates menus
> > and legends thinks that all layers are "normal" layers.
> 
> Another problem that comes with "remote" layers is buffering.

Yes.  I've already thought about caching since on a slow line it
takes a while to retrieve the remote image.

> We saw that with the postgis tables already, 
> but I also expect this to be a problem with your layers, too.

True.

I thought about hooking an image cache into the WMSLayer.GetMapImg().

I've also thought about buffering the current image locally so
it doesn't have to be retrieved when the image needs to be rendered
again (for hide/unhide for example).

> We do not only need layers specific information, 
> but also general and layer specific buffering methods.

What kinds of data need to be buffered with postgis tables?

I'd expect this to be tons of rows from SQL queries.  Is that true?

Anything else that should be buffered/cached in Thuban?

Regards,

	Joey

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