[OpenLayers-Users] How to add an overlay to the map, but not select it by default

[Adrian Popa]

Thanks for the tips,

I'm using mapserver because I managed to migrate my setup from an 
existing mapserver installation (using a different frontend), and I 
didn't have the time to dig into enabling (and troubleshooting WMS). 
When the time comes, all Mapserver objects will become WMS.

I am already using the server side layer separation/generation trick to 
include yahoo/google/openstreetmaps. This reduces page load time 
significantly (because it doesn't have to load all the support js). My 
question is: is this true also for overlay layers which are not enabled 
- meaning would I get a moderate/significant boost in load time if I 
don't add the overlays on page load, but on some user action?

Thanks,
Adrian

Alexandre Dube wrote:
> Hi,
>
>  Some hints :
>
>  - you should use OpenLayers.Layer.WMS instead of MapServer.  I don't 
> know the reason but some OL devs occasionally say this.
>  - don't have too many OpenLayers.Layer objects in your map.  It's 
> slow.  If you can, have many server-side layers single OL layers.  
> Simply define them in the 'layers' param property, seperated by ',' if 
> your OL layer is WMS or ' ' if MapServer :
>    (WMS) layers:'mylayer1,mylayer2,mylayer3' or
>    (MapServer) layers:'mylayer1 mylayer2 mylayer3'
>
>  Just some hints,
>
> Regards,
>
> Alexandre
>
> Adrian Popa wrote:
>> Thanks! This is a cleaner way to do it :)
>>
>> Alexandre Dube wrote:
>>> Hi,
>>>
>>> Adrian Popa wrote:
>>>> Hello everyone,
>>>>
>>>> I'm trying to add several overlay layers (from mapserver) to an 
>>>> openlayers map. Everything works as expected, but when the map 
>>>> loads, all the overlay layers are selected. I would like to have 
>>>> the ability (programmatically) to select which layers are selected 
>>>> by default. Here's an example of how I enable an overlay layer:
>>>>
>>>> var rtc = new OpenLayers.Layer.MapServer("Test", 
>>>> "http://terra/cgi-bin/mapserv", { map='/var/www/html/map/rtc.map', 
>>>> transparent:true, format:'png',
>>>> map_imagetype: 'agg',layers: 'mylayer', maxExtent: new 
>>>> OpenLayers.Bounds(20.26, 43.16, 29.70, 48.46), maxResolution: 
>>>> 156543,units: 'm'},
>>>> { isBaseLayer:false, projection: sphericalMercator, singleTile: 
>>>> 'true'});
>>>>
>>>>   
>>>
>>> Add visibility:false to your options :
>>>
>>> { isBaseLayer:false, projection: sphericalMercator, singleTile: 
>>> 'true', visibility:false}
>>>
>>>
>>>> map.addLayers([rtc]);
>>>>
>>>> I was unable to find a method in the documentation to allow me to 
>>>> 'deselect' specific layers. If there is, I would appreciate a pointer.
>>>>
>>>> Thanks in advance,
>>>> Adrian
>>>>
>>>> _______________________________________________
>>>> Users mailing list
>>>> Users at openlayers.org
>>>> http://openlayers.org/mailman/listinfo/users
>>>>   
>>>
>>>
>>
>>
>
>