[Chameleon] adding several layers from the same external WMS

[bartvde@xs4all.nl]

Hi list,

in Chameleon there is the possibility to add layers from a treeview to the
map.

In this case if a user adds e.g. 5 layers from the same external WMS, 5
LAYERS are created in the session MAP file, all with a connection type
WMS.

This means 5 requests to the external WMS per Chameleon MAP refresh. In
theory, this could be solved by asking just one image to the WMS server
(layers=A,B,C,D,E). Ofcourse, this has the assumption that the five layers
from the external WMS are in sequence on top of each other, and not some
other layer in between.

I have also noticed that when using the layers=A,B,C,D,E type of syntax,
the Web Map Context (save, upload) does not function any more.

Any thoughts on this, could this be a potential performance enhancement
for Chameleon, and would this require changes in PHP/Mapscript or in the
Chameleon PHP code?

Best regards,
Bart