[Mapserver-dev] WMS: nested groups

[Daniel Morissette]

Silke Reimer wrote:
> 
> We are working on a project where we need nested layers in more than
> one level within a WMS server.
> 
> Currently the WMS implementation of the UMN MapServers allows one
> grouping level by assigning a group to several layers. The groupname
> then appears as nested layer into the Capabilities-Document.
> 
> I thought of a possibility how to enhance the UMN MapServer to allow
> more than one grouping level and came to the idea to add a new layer
> type, named 'grouplayer' which is only a virtual layer. Such I can
> define a full tree of nested layers (see example below).
> 

Actually, the ability to support deeper nesting was added not long ago 
in 4.3/4.4. More details in bug 776:
http://mapserver.gis.umn.edu/bugs/show_bug.cgi?id=776

> - what is about nested layers of the wfs and wcs? Probably this code
>   has to be adapted as well (this has not been important for my
>   implementation so I left it out so far).

I can't speak for WCS, but I don't think that grouping WFS layers 
can/should be done. The reason is that WFS layers are exposed as Feature 
Types, and all features in a given feature type need to share a common 
schema (attributes). There is no way in MapServer to verify or guarantee 
that features from two layers could share the same schema so we cannot 
safely support that. However, if you need to group multiple data files 
into a single WFS feature type you could always use a tileindex on a 
single layer in your mapfile.

Daniel
-- 
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  Daniel Morissette               dmorissette at dmsolutions.ca
  DM Solutions Group              http://www.dmsolutions.ca/
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