[Chameleon] combine ExpressionBuilder / ExtractWFSData

[William A. Bronsema]

Hi Bart,

bartvde@xs4all.nl wrote:

> Hi Bill,
> 
> if I add this SharedResource to my template will I always get the results
> in GML? In other words, will it decrease the performance of my application
> even in a situation in which a user does not choose to download his
> selection in GML?
> 
> Do you get the GML through the Mapserver WFS interface?
> 

Yes, there is a performance cost associated with adding this shared 
resource.  The ExpressionBuilder widget normally just sets the filter on 
the layer and filters when the map is drawn.  When you include the 
shared resource a separate "executeWFSGetfeature" call is made on the 
layer and the results are parsed into an array.

I'm not sure what you mean when you say "[when] a user does not choose 
to download his selection in GML".  This "executeWFSGetfeature" call 
always returns a gml file.  There is no relationship between the 
ExpressionBuilder widget and the ExtractWFSData.  The ExtractWFSData 
widget does allow you to select an output format, the ExpressionBuilder 
does not.

Yes, the GML is obtained through the Mapserver WFS interface via a 
PHPMapscript "executeWFSGetfeature" call on the layer.


I hope that answers your questions.

Regards,
Bill

-- 

William A. Bronsema, C.E.T.
Applications Developer,
DM Solutions Group Inc.

http://www.dmsolutions.ca
email: wbronsema@dmsolutions.ca
Phone: (613) 565-5056 ext.25
Fax :  (613) 565-0925
____________________________________