[Mapbender-users] implement "layer conflicts" - mod_treefolder2.php

[karsten vennemann]

Greetings everyone,

I am working on implementing a function that I need for my mapping
application. The map has a lot of polygon layers and for its users it is
very confusing once multiple layers are switched on that are covering each
other. The users have a hard time easily and clearly know which one is drawn
on top on the map.
Thus I want to set layers to "conflict with each other". Turning on a Layer
that has other layers set to be conflicting with it will trigger all
conflicting layers to automatically be switched off.
For example a layer 1)  "Percentage of Poor people age 65 and over in 2000"
will conflict with a layer 2) "Percentage of Poor people age 65 and over in
2007". Thus if layer 1) is turned on layer 2) automatically will be switched
off and so on.
I am working to extended/amend the function "handleSelectedLayer" in
mod_treefolder2.php. 
For now I just was testing and learning what the function does thus I did
just set some hard coded conflicts using a new variable like and switched
the layer off if a certain (also hard coded layer) is switched on:

if(layername == "People_in_Institutions_02" && status == 1){
mylayerconflicts[0] = "Percentage_of_People_in_Poverty_per_County_2005";
parent.handleSelectedLayer_array(mapObj, mywms, mylayerconflicts, type, 0);
}

This does what I wanted to accomplish (the layer is switched off and not
shown on the map any more, however the checkbox in the tree is still
"checked". 

What would be the best way/ a way to uncheck the checkbox as using java
script in the tree ?

Any other Ideas on how to generally best implement this?

I was thinking to implement reading an array/list from a new column in a
database table where each layer could have a list of conflicting layers/
groups of layers stored. The array could then be used in a loop to switch
off all conflicting layers on the client side. Later I also could add an
admin web interface to enter the values for conflicts for each layer.
Cheers
 
Karsten Vennemann