[OpenLayers-Users] Query only in visible layers

[Ivan Carreira]

Thanks for the replies.  I'll work on it.

Regards, 

Iván









> Are you using firebug ?  If not, you should.  It's a great javascript 
> tool.  Put breakpoints where needed and you'll see the functions and 
> object properties available for what you need.
> 
>   Since you're starting with OpenLayers, you should try to make the 
> query work for one layer only ( do no loop in the map layers yet ).
> 
>   It could looks like this :
> 
>         if(!event)
>             return;
> 
>         if(!layer.getVisibility() || !layer.inRange)
>             return;
> 
>          // carry on with your query
> 
> Regards,
> 
> Alexandre
> 
> 
> Ivan Carreira wrote:
> > 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);
> > > >
> > > >
> >
> > >
> >
> > ------------------------------------------------------------------------
> > Ahora, GRATIS Hotmail en tu móvil ¡Descúbrelo aquí! 
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> > ------------------------------------------------------------------------
> >
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> >   
> 
> 
> -- 
> Alexandre Dubé
> Mapgears
> www.mapgears.com
> 

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