[Chameleon] ExpressionBuilder: 2 GetMap requests

[Bart van den Eijnden]

Hi list,

I was just thinking about one thing. Currently the Chameleon  
ExpressionBuilder needs 2 GetMap requests in order to draw a selection.  
The first, bottom-most layer is just a normal WMS layer in the normal  
style defined on the server, the top-most layer is the selection displayed  
eg in red using SLD UserStyle.

I was re-studying the SLD spec and this should be possible with only 1  
GetMap request, I only don't know if Mapserver support this .... but Paul  
or Assefa might know?

You can combine a UserStyle with a NamedStyle in an SLD, where you use the  
NamedStyle default (which is advertized by Mapserver WMS in the  
capabilities). An example from the SLD spec (the namedstyle is drawn at  
the bottom):

<StyledLayerDescriptorversion="1.0.0"><NamedLayer><Name>Roads</Name><UserStyle><FeatureStyleType><Rule><LineSymbolizer><Geometry><ogc:PropertyName>center-line</ogc:PropertyName></Geometry><Stroke><CssParametername="stroke">#aaaaff</CssParameter><CssParametername="stroke-width">5.0</CssParameter></Stroke></LineSymbolizer></Rule></FeatureTypeStyle></UserStyle><NamedStyle><Name>default</Name></NamedStyle></NamedLayer></StyledLayerDescriptor>

Any thoughts?

Best regards,
Bart

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