[fusion-trac] #79: Allowing for Nested Groups in Legend when Using MapServer

[Fusion]

#79: Allowing for Nested Groups in Legend when Using MapServer
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   Reporter:  schneiderei  |       Owner:  madair
       Type:  enhancement  |      Status:  new   
   Priority:  P2           |   Milestone:  1.1   
  Component:  MapServer    |     Version:  1.0.6 
   Severity:  Major        |    Keywords:        
External_id:               |       State:  New   
    Browser:  All          |          Os:  All   
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 MapServer seems to restrict organising layers to two levels: One can have
 regular map layers right at the top-most level, or one can specify groups
 and assign the layers to them. Assigning groups to groups, that is,
 specifying nested groups in a tree is not supported. This limitation is
 reflected in the file MapServer/php/LoadMap.php where a line of comment
 mentiones this limitation.

 I have played with that piece of code a bit, and it seems that the
 limitation can easily be overcome. In the function getGroupObject(..), the
 layer that is passed to the function can be queried for its parent. If the
 layer corresponds to the group, it will know about it parent group, and
 this information can be stored in group->parent as well as in
 group->parentUniqueId.

 (I think that there is a bug where the function is called, a few lines
 above, because the layer that is passed to the function may or may not be
 the group layer in question. The function queries for group information
 such as METADATA "groupLegendLabel" which returns empty results if the
 layer is not the group layer of interest. I'll post a separate ticket on
 this.)

 After having changed the code in this way, the groups are indeed nested in
 the legend, they behave as they should when checked and unchecked, and the
 maps are drawn correctly accounting for the visibility status of the
 groups and layers.

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Ticket URL: <http://trac.osgeo.org/fusion/ticket/79>
Fusion <http://trac.osgeo.org/fusion>
Fusion is a web-mapping application development framework for MapServer and MapGuide OS.