[OpenLayers-Users] Query only in visible layers

[Ivan Carreira]

Thanks
for the help. I am starting to use openlayers and I do not know much
about this. 
The idea is: 
-Deactivating a layer in the legend,  make the query, and not display the popup
-Activating a layer in the legend, make the query, and not display the popup

 Being
tested with the following: 


var showInfo = function(event) {
                var layers  = map.layers;                              
            
            if(event)
            {
                 for (var i = 0; i < layers.length; i++) {

                      if (!layers[i].getVisibility())
                
                {


 but I do not know how to continue.

 Regards,

Iván






> 
> Hi,
> 
>   Do you mean visible OpenLayers layers or server side-layers ?  Do you 
> use (1) one OL layer per server-side layer or (2) are they all in the 
> same OL layer ?
> 
>   If (1) : loop through your map layers for each visible/inRange layer 
> to get their params.['LAYERS'] property.  If they come from the same 
> server, you can merge them in a single request.
> 
>   If (2) : If you use MapServer and you have direct access to the 
> mapfile, you could do the following.  Please, anyone correct me if I'm 
> wrong, but I think getfeatureinfo requests are made regardless of a 
> layer's minscaledenom or maxscaledenom property.  So you could create a 
> template with leg_layer_minscale and leg_layer_maxscale values to get 
> theses values from the server-side into a javascript array.  Also, add 
> the layer name at the same time (because that's the value to be added to 
> the query_layers query property). Then, on click, you could loop through 
> this array to check that the layers are currently visible (compare with 
> current scale).  See that (3) link for more details.  Does that make sense ?
> 
> (3) http://mapserver.org/output/html_legend.html
> 
> Regards,
> 
> Alexandre
> 
> Ivan Carreira wrote:
> > Hi all,
> >
> >  
> >
> > I have a problem.
> >
> > I need an expression to limit queries only to the layers that are visible at that time on the map.
> > Queries are displayed via a popup.
> > The code where queries are made and displayed in the popup is as follows:
> >
> > var showInfo = function(event) {
> > 				
> >                 var pixel = event.xy;
> >                 var lonlat = this.getLonLatFromPixel(pixel);
> >                 var message = null;
> >                 var params = {}; 
> >                 params['service'] = 'wms'; 
> >                 params['request'] = 'GetFeatureInfo'; 
> >                 params['version'] = '1.1.1'; 
> >                 params['info_format'] = 'text/plain';
> >                 params['srs'] = this.getProjection();
> >                 params['bbox'] = this.getExtent().toBBOX(6);
> >                 params['width'] = this.getSize().w; 
> >                 params['height'] = this.getSize().h;
> >                 params['feature_count'] = 1; 
> >                 params['x'] = pixel.x; .
> >                 params['y'] = pixel.y; 
> >                 params['layers'] = 'camino'; 
> >                 params['query_layers'] = 'camino';
> > 		
> > 		new OpenLayers.Request.GET({
> > 			url: server,
> > 			async: false,
> > 			params: params,
> > 			success: function(data) {
> > 				message = data.responseText;
> > 			}
> > 		});
> > 		
> > 		
> > 		
> > 		message = getHTML(message);
> > 		
> > 		
> > 		var popup = new OpenLayers.Popup.FramedCloud('popup', lonlat, null, message, null, true, null);
> > 		
> > 		this.addPopup(popup);
> >
> > };//End of function showInfo()
> >
> > 	map.events.register('click', map, showInfo);
> >   
> >

> 

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