AW: [OpenLayers-Users] Re: remove a layer by name

[Arnd Wippermann]

Hi,

Have you the SelectFeatureControl active? That may be the issue. 

If you use the Control with an array of layers, it seems, that OpenLayers
creates a temporary layer (OpenLayers.Layer.Vector.RootContainer) with all
the features of the selectable layers, if the Control is active. 
Deleting the layer of the features doesn't delete the features on the
temporary layer.
Before deleting a layer one have to deactivate the Control.

Arnd
 

-----Ursprüngliche Nachricht-----
Von: openlayers-users-bounces at lists.osgeo.org
[mailto:openlayers-users-bounces at lists.osgeo.org] Im Auftrag von Puneet
Kishor
Gesendet: Montag, 26. September 2011 20:12
An: armin.burger at gmx.net
Cc: openlayers-users at lists.osgeo.org
Betreff: Re: [OpenLayers-Users] Re: remove a layer by name


On Sep 26, 2011, at 12:57 PM, Armin Burger wrote:

> 
> 
> On 26/09/2011 05:31, Puneet Kishor wrote:
> 
>> 
>> The following code does what I want --
>> 
>> 	var lyr_list = map.getLayersByName("a_layer");
>>         if (typeOf(lyr_list) === "array") {
>>         	for (var i in lyr_list) {
>>                 	lyr_list[i].removeAllFeatures();
>>                         removeLayer(lyr_list[i]);
>>                 }
>> 	}
>> 
> > Surely, the above couldn't be the most optimum way, could it?
> 
> 
> it will not change anything for your particular case, but I usually
reference layers via their ID. This requires to add the ID after creation.
> 
> something like
> 
> var myLayer = new OpenLayers.Layer...; 
> myLayer.addOptions({id:'theLayerId'});
> 
> then you can always access the layer later on like
> 
> var mapLayer = map.getLayer('theLayerId');


Thanks Armin, but you are correct, it doesn't change anything for me. I have
no problems "getting" the layer. I just am unable to use that layer to
remove it effectively (and, I'd prefer to continue getting the layer via its
name).

Some of the things I don't understand --

Why is a layer list returned and not just a layer when I `getLayersByName`?
In other words, under what use case would there be more than one layers with
the same name?

Why is a layer removed from the layer switcher via `removeLayer(layerObj)`
but its features not removed? What could be the use of that functionality?

Why are the features of a layer removed from the map via
`removeAllFeatures()` but the layer not removed? (although I can see the
point of that).

Having a clear distinction between removing the features, removing the
layer, and destroying the layer would also be very useful.


> 
> 
> For completely deleting a layer it might be necessary to also run the
.destroy() method on the layer, but I'm not sure when this is required and
when not.
> 
> Regards
> Armin
> _______________________________________________
> Users mailing list
> Users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/openlayers-users

_______________________________________________
Users mailing list
Users at lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/openlayers-users