[OpenLayers-Users] remove a layer by name

[Puneet Kishor]

On Sep 26, 2011, at 2:00 PM, Arnd Wippermann wrote:

> Hi,
> 
> Have you the SelectFeatureControl active? That may be the issue. 


Exactly. That is most likely the issue because, indeed, I do have SelectControl active.

Should this tidbit be a part of the documentation? Right where removeLayer is discussed?

Thanks much.


> 
> 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