[OpenLayers-Users] Question on having multiple layers

[Gregor Mosheh]

Ali Khan wrote:
> Is there anyway one can make a select box on the page and on change have 
> it reference the appropriate layer to show in OpenLayers?

Sure. While loading your layers in a loop (that's how I like doing it) 
store the layers into an associative array so they can be referenced by 
name. Give the HTML checkboxes a onClick handler to fetch and layer and 
toggle it.

Should look something like this:

<input type="checkbox" name="toggle[]" value="Oceans" 
onClick="toggleLayer('Oceans');"/> Oceans

<script>
function toggleLayer(layername) {
   var l = ALL_LAYERS[layername]; if (!l) return;
   l.setVisibility(! l.getVisibility() );
}
</script>



> Also for each layer we want to have a seperate getFeatureinfo query as 
> each layer contains different data. How do we do this? can we do 
> layer.events.register instead of map.events.register for instance so 
> that each layer has its own on click event?

I experimented with that a month ago using WFS layers, and found that 
only one layer can use click-to-query at a time. I may be wrong about 
that...

-- 
Gregor Mosheh / Greg Allensworth
System Administrator, HostGIS cartographic development & hosting services
http://www.HostGIS.com/

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  only if you can restore." - AMANDA