[OpenLayers-Users] multiple layers... best performance?

[Alexandre Dube]

Hi,

  It's faster to get one big getMap request than 10 small ones.  I'm no 
GeoServer user, but I'm pretty sure you can set minscale/maxscale values 
to your server-side layers to display your layers only when necessary.  
That would be a gain of performance.

Regards,

Alexandre

pere roca ristol wrote:
> hi all, 
> on my webapp I have distributed legends where you can switch on/off 
> different layers. All of these layers refer to the same GeoServer. 
> As far as I know, I can design my webapp in two ways: 
> 1) Just an Openlayers layer and I add/remove layers from layers 
> parameter when user switch on/off a layer 
>
>    layer = new OpenLayers.Layer( "OpenLayers 
> WMS","http://myGeoServer/wms",{layers: layer1,layer2...} 
>
> 2) create "on-the-fly" a new OpenLayers.Layer with a function when 
> user selects a still not visible layer: 
>             var add_lay=function(layerName,lay) 
>                                 { 
>                          var new_lay="edit_"+layerName+" =new 
> OpenLayers.Layer.WMS( 'my WMS','http://myGeoserver' 
> <http://myGeoserver%27>,{layers:'topp:"+lay+"'} );";           
>  eval(new_lay);
>                       eval("map.addLayer(edit_"+layerName+")");
>                                 } 
>
> The problem of the first is that each time a layer is switched on/off 
> or zoom in/out, a big GetMap request (what about 10 layers?) must be 
> done and takes more time than usual. 
> The problem of the second one is that the more layer we add on the top 
> of an openlayer application, the more the application slow down. 
>
> In terms of performance, which is the best option? 
>
> thanks! 
> Pere Roca
>
> -- 
> Pere Roca Ristol
> Biòleg i especialista GIS
> Museo Nacional de Ciencias Naturales (CSIC)
>
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-- 
Alexandre Dubé
Mapgears
www.mapgears.com