groups and WMS

[Sean Gillies]

On Sep 29, 2005, at 12:54 PM, Armin Burger wrote:

> Dear all,
>
> I have a question about the behaviour of groups in a WMS. When I define
> 2 layers belonging to the same group, I see both layers nested under 
> the
> same group layer in the capabilities file.
>
> But I can only access the group as a WMS layer from a client. When I
> want to access the single layers belonging to that group I get an
> exception. That is in principal ok, but client programs might allow to
> select the single nested layers and the map will not be displayed
> because of the exception. Also the reason for grouping layers is quite
> often to have layers with different accuracy/resolution that should be
> swapped depending on the scale. So this should happen behind the scenes
> without the client noticing it.
>
> So my question is, why are the layers belonging to the same group
> displayed at all in the WMS capabilities if they cannot be used as
> single ones? Would it not make sense to just return the group as a WMS
> layer instead?
>
> Armin
>
>

Armin,

I've been thinking about this too. In your case, I think it is a WMS 
client bug: you should be able to access any Layer no matter how deep 
it is nested.

Sean

--
Sean Gillies
sgillies at frii dot com
http://zcologia.com