[OpenLayers-Users] creating a persistent vector/feature object from wfs

[Christopher Schmidt]

On Thu, Jun 12, 2008 at 02:36:56PM +0200, François Van Der Biest wrote:
> 2008/6/12, G. Allegri <giohappy at gmail.com>:
> >
> > Hello list.
> > I need to call a wfs to retrieve a multipolygon vector layer. As it's
> > quite huge (about 15000 vertices), I'd like to call it once (full
> > extent) and then "copy" it in a vector object to avoid calling wfs
> > when zooming and panning.
> 
> 
> Just one question : will browsers be able to handle such an amount of data ?
> I'm interested in some feedback on this.

Depending on the browser, 'sort of'.

FF3 and Safari3 should handle this reasonably well.
FF2 will work *okay* for display, but dragging the map will be slow: as
you are more zoomed in on a large shape (less vertices in view) the
rendering gets quicker.

If you don't do map dragging, it's not noticably slow to do most of
these things. For an example of a pretty complex vector map, you can
check out http://crschmidt.net/mapping/choropleth.html -- I don't know
the exact number of vertices, but 'large' is not an understatement :)

I expect that parsing an XML document that large may prove problematic:
anything larger than 500k is somewhat 'danger, danger', in my mind.

If it were 7500 features of two vertices, it would be much slower than
if it were 1 feature with 15000 vertices.

 In any case, in IE, you wouldn't even bother trying at this size.

Regards,
-- 
Christopher Schmidt
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