[mapserver-users] cascading mapserver

[Daniel Morissette]

Bart van den Eijnden wrote:
> 
> The only problem is that my vendor specific parameter (query_params) is not
> static, it is dynamic. Everytime the client makes a selection, a different
> where clause (like ID = 30) is sent in the query_params part of the
> request.
> 

MapServer won't do that kind of stuff.


> Does anybody know if OGC has something in their specification for
> dynamically querying WMS layers and retrieving the selection e.g. in red in
> the image retrieved?
> 

I think what you're looking for is closer to GetFeatureInfo than to
GetMap.  One thing that is not mentioned in the OGC WMS spec, but that
is not forbidden either is that we could advertize image formats such as
image/png, image/jpeg as INFO_FORMATs for the GetFeatureInfo
capabilities.  Then a client map server could send a GetFeatureInfo
request with INFO_FORMAT=image/png, and the result of this type of
request would be a map with the selected polygons (or points/lines)
highlighted, exactly what MapServer's QUERYMAP feature does today.

None of this is currently possible with MapServer at the moment, but
that could be a worthwhile enhancement that would be compatible with the
OGC specs (you could file this in bugzilla if you like).

-- 
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 Daniel Morissette               morissette at dmsolutions.ca
 DM Solutions Group              http://www.dmsolutions.ca/
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