[OpenLayers-Dev] Some questions about WFS-T

Christopher Schmidt crschmidt at metacarta.com
Mon Apr 2 16:07:13 EDT 2007


On Mon, Apr 02, 2007 at 10:00:34PM +0200, Andrea Aime wrote:
> Christopher Schmidt ha scritto:
> 
> >>Another thing I noticed, this time in the wfs-states.html sample, is
> >>that while the states layer is loading, firefox is frozen, and 
> >>performing a CPU intensive task (I guess it's GML parsing).
> >>The same goes with IE7, with the aggravation that IE suggests killing
> >>the script that's blocking it (with a popup).
> >
> >Yes. GML parsing is slow. 
> 
> I'm under the impression that you're requesting all the properties
> from a WFS layer, while using only the geometric one (the first you
> find I guess, since there may be many) to depict the layer.
> It would be better to just load what you need, and then eventually
> load the full feature on demand. On a layer with a crazy number
> of properties like states (more than 100 if I remember properly)
> it should help.

Nope. The states example doesn't load any attributes. The data may be
there: it's not parsed by default -- only if you turn on the
extractAttributes option on the layer. 

Parsing the coordinate string is usually the worst of it, but there's
also a pathological bad behavior with large polygons (in the thousands
of coordinates range), though I'm not sure if that is triggered here. 

Regards,
-- 
Christopher Schmidt
MetaCarta



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